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Chicken

November 29, 2023

For the culinary use of chickens, see Chicken as food. For other uses, see Chicken (disambiguation) and Chooks (disambiguation).
"Rooster" and "Roosters" redirect here. For other uses, see Rooster (disambiguation).
"Cockerel" redirects here. For the Fabergé egg, see Cockerel (Fabergé egg).

The chicken (Gallus domesticus) is a domesticated species that arose from the red junglefowl, originally from Southeast Asia. They have also partially hybridized with other wild species of junglefowl (the grey junglefowl, Ceylon junglefowl, and green junglefowl).[1] Rooster and cock are terms for adult male birds, and a younger male may be called a cockerel. A male that has been castrated is a capon. An adult female bird is called a hen, and a sexually immature female is called a pullet. Humans keep chickens primarily as a source of food (consuming both their meat and eggs) or as pets. Traditionally, they were also bred for cockfighting, which is still practiced in some places. Chickens domesticated for meat are broilers, and for eggs, they are layers.

Chicken
A rooster (left) and hen (right) perching on a roost
Domesticated
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Galliformes
Family: Phasianidae
Genus: Gallus
Species:
G. domesticus
Binomial name
Gallus domesticus
Chicken distribution

Chickens are one of the most common and widespread domestic animals, with a total population of 23.7 billion as of 2018,[2] up from more than 19 billion in 2011. There are more chickens in the world than any other bird. There are numerous cultural references to chickens—in myth, folklore, and religion, as well as in language and literature.

Genetic studies have pointed to multiple maternal origin theories within South Asia, Southeast Asia, and East Asia,[3] but the clade found in the Americas, Europe, the Middle East, and Africa originated from the Indian subcontinent. From ancient India, the chicken spread to the Eastern Mediterranean. They appear in ancient Egypt in the mid-15th century BC, with the "bird that gives birth every day" having come from the land between Syria and Shinar, Babylonia, according to the annals of Thutmose III.[4][5][6] They are known in ancient Greece from the 5th century BC.[7][8]

Terminology

 
In most breeds the adult rooster can be distinguished from the hen by his larger comb.
 
Comb of a hen.

An adult male is a called a cock or (in the United States) a rooster, and an adult female is called a hen.[9][10]

Other terms are:

  • Biddy: a newly hatched chicken[11][12]
  • Capon: a castrated or neutered male chicken[a]
  • Chick: a young chicken[13]
  • Chook /tʃʊk/: a chicken (Australia/New Zealand, informal)[14]
  • Cockerel: a young male chicken less than a year old[15]
  • Dunghill fowl: a chicken with mixed parentage from different domestic varieties.[16]
  • Pullet: a young female chicken less than a year old.[17] In the poultry industry, a pullet is a sexually immature chicken less than 22 weeks of age.[18]
  • Yardbird: a chicken (southern United States, dialectal)[19]

Chicken may also mean a chick (see for example Hen and Chicken Islands).[20] In fact, chicken was originally a term only for an immature, or at least young, bird.[when?] In older sources, and still often in trade and scientific contexts, chicken as a species are typically referred to as common fowl or domestic fowl.[21]

In Australian vernacular English the word chook provides the generic term for the species (e.g. "a cooked chook" or "she keeps chooks"); which enables chicken to commonly retain its original sense of a young or recently hatched bird. Chick is then rarely used to mean chicken, but is mainly used in Merriam-Webster's "Sense 1b" viz. the young of any bird.

Etymology

According to Merriam-Webster, the term rooster (i.e., a roosting bird) originated in the mid- or late 18th century as a euphemism to avoid the sexual connotation of the original English cock,[22][23][24] and is widely used throughout North America. Roosting is the action of perching aloft to sleep at night.[25]

Biology and habitat

Chickens are omnivores.[26] In the wild, they often scratch at the soil to search for seeds, insects, and even animals as large as lizards, small snakes,[27] or sometimes young mice.[28]

The average chicken may live for 5–10 years, depending on the breed.[29] The world's oldest known chicken lived for 16 years, according to Guinness World Records.[30]

Roosters can usually be differentiated from hens by their striking plumage of long, flowing tails and shiny, pointed feathers on their necks (hackles) and backs (saddle), which are typically of brighter, bolder colours than those of females of the same breed. However, in some breeds, such as the Sebright chicken, the rooster has only slightly pointed neck feathers, the same colour as the hen's. Identification can be made by looking at the comb, or eventually by the development of spurs on the male's legs (in a few breeds and in certain hybrids, the male and female chicks may be differentiated by colour).

Adult chickens have a fleshy crest on their heads called a comb, or cockscomb, and hanging flaps of skin on either side under their beaks called wattles. Collectively, these and other fleshy protuberances on the head and throat are called caruncles. Both the adult male and female have wattles and combs, but in most breeds, these are more prominent in males. A 'muff' or 'beard' is a mutation found in several chicken breeds that causes extra feathering under the chicken's face, giving the appearance of a beard.[31]

Domestic chickens are not capable of long-distance flight, although lighter chickens are generally capable of flying for short distances, such as over fences or into trees (where they would naturally roost). Chickens may occasionally fly briefly to explore their surroundings, but generally do so only to flee perceived danger.

Behavior

Social behaviour

See also: Empathy in chickens
 
Hen with chicks

Chickens are gregarious birds and live together in flocks. They have a communal approach to the incubation of eggs and raising of young. Individual chickens in a flock will dominate others, establishing a pecking order, with dominant individuals having priority for food access and nesting locations. Removing hens or roosters from a flock causes a temporary disruption to this social order until a new pecking order is established. Adding hens, especially younger birds, to an existing flock can lead to fighting and injury.[citation needed]

Chickens may occasionally gang up on a weak or inexperienced predator. At least one credible report exists of a young fox killed by hens.[32][33][34] If a chicken is threatened by predators, stress, or is sick, it may puff up its feathers.[35]

Vocalizations

When a rooster finds food, he may call other chickens to eat first. He does this by clucking in a high pitch as well as picking up and dropping the food. This behaviour may also be observed in mother hens to call their chicks and encourage them to eat.

A rooster's crowing is a loud and sometimes shrill call and sends a territorial signal to other roosters.[36] However, roosters may also crow in response to sudden disturbances within their surroundings.

Hens cluck loudly after laying an egg and also to call their chicks. Chickens also give different warning calls when they sense a predator approaching from the air or on the ground.[37]

Crowing

"Cockadoodledoo" and "Cocka-doodle-doo" redirect here. For the nursery rhyme, see Cock a doodle doo.
 
Bergische Kräher crowing
The long crowing of a Bergische Kräher
Normal length crowing (with audio). Long-crowing chickens have a longer crow.

Roosters almost always start crowing before four months of age. Although it is possible for a hen to crow as well, crowing (together with hackles development) is one of the clearest signs of being a rooster.[citation needed]

Rooster crowing contests are a traditional sport in several countries, such as Germany, the Netherlands, Belgium,[38] the United States, Indonesia and Japan. The oldest contests are held with longcrowers. Depending on the breed, either the duration of the crowing or the times the rooster crows within a certain time is measured.

Courtship

To initiate courting, some roosters may dance in a circle around or near a hen (a circle dance), often lowering the wing which is closest to the hen.[39] The dance triggers a response in the hen[39] and when she responds to his call, the rooster may mount the hen and proceed with the mating.

More specifically, mating typically involves the following sequence:

  1. Male approaching the hen
  2. Male pre-copulatory waltzing
  3. Male waltzing
  4. Female crouching (receptive posture) or stepping aside or running away (if unwilling to copulate)
  5. Male mounting
  6. Male treading with both feet on hen's back
  7. Male tail bending (following successful copulation)[40]

Nesting and laying behaviour

Hens will often try to lay in nests that already contain eggs and have been known to move eggs from neighbouring nests into their own. The result of this behaviour is that a flock will use only a few preferred locations, rather than having a different nest for every bird. Hens will often express a preference to lay in the same location. Two or more hens may try to share the same nest at the same time. If the nest is small or one of the hens is particularly determined, this may result in chickens trying to lay on top of each other. There is evidence that individual hens prefer to be either solitary or gregarious nesters.[41]

Broodiness

 
Chicken eggs vary in colour depending on the breed, and sometimes, the hen, typically ranging from bright white to shades of brown and even blue, green, light pinkish and purple.

Under natural conditions, most birds lay only until a clutch is complete and they will then incubate all the eggs. Hens are then said to "go broody". The broody hen will stop laying and instead will focus on the incubation of the eggs (a full clutch is usually about 12 eggs). She will sit or 'set' on the nest, fluffing up or pecking in defense if disturbed or removed. The hen will rarely leave the nest to eat, drink, or dust-bathe.[35] While brooding, the hen maintains the nest at a constant temperature and humidity, as well as turning the eggs regularly during the first part of the incubation. To stimulate broodiness, owners may place several artificial eggs in the nest. To discourage it, they may place the hen in an elevated cage with an open wire floor.

Breeds artificially developed for egg production rarely go broody, and those that do often stop part-way through the incubation. However, other breeds, such as the Cochin, Cornish and Silkie, do regularly go broody, and make excellent mothers, not only for chicken eggs but also for those of other species — even those with much smaller or larger eggs and different incubation periods, such as quail, pheasants, ducks, turkeys, or geese.

Hatching and early life

 
Two Lavender Orpington chicks.
 
A group of chicks

Fertile chicken eggs hatch at the end of the incubation period, about 21 days.[39] Development of the chick starts only when incubation begins, so all chicks hatch within a day or two of each other, despite perhaps being laid over a period of two weeks or so. Before hatching, the hen can hear the chicks peeping inside the eggs and will gently cluck to stimulate them to break out of their shells. The chick begins by pipping: pecking a breathing hole with its egg tooth towards the blunt end of the egg, usually on the upper side. The chick then rests for some hours, absorbing the remaining egg yolk and withdrawing the blood supply from the membrane beneath the shell (used earlier for breathing through the shell). The chick then enlarges the hole, gradually turning round as it goes, and eventually severing the blunt end of the shell completely to make a lid. The chick crawls out of the remaining shell, and the wet down dries out in the warmth of the nest.

Hens usually remain on the nest for about two days after the first chick hatches, and during this time the newly hatched chicks feed by absorbing the internal yolk sac. Some breeds sometimes start eating cracked eggs, which can become habitual.[42] Hens fiercely guard their chicks and brood them when necessary to keep them warm, at first often returning to the nest at night. She leads them to food and water and will call them toward edible items but seldom feeds them directly. She continues to care for them until they are several weeks old.

Reproduction

Sperm transfer occurs by cloacal contact between the male and female, in a maneuver known as the 'cloacal kiss'.[43] As with birds in general, reproduction is controlled by a neuroendocrine system, the Gonadotropin-Releasing Hormone-I neurons in the hypothalamus. Locally to the reproductive system, reproductive hormones such as estrogen, progesterone, gonadotropins (luteinizing hormone and follicle-stimulating hormone) initiate and maintain sexual maturation changes. Over time there is reproductive decline, thought to be due to GnRH-I-N decline. Because there is significant inter-individual variability in egg-producing duration, it is believed to be possible to breed for further extended useful lifetime in egg-layers.[44]

Embryology

(Video) Earliest gestation stages and blood circulation of a chicken embryo

Chicken embryos have long been used as model organisms to study developing embryos. Large numbers of embryos can be provided by commercial chicken farmers who sell fertilized eggs which can be easily opened and used to observe the developing embryo. Equally important, embryologists can carry out experiments on such embryos, close the egg again and study the effect later on. For instance, many important discoveries in the area of limb development have been made using chicken embryos, such as the discovery of the apical ectodermal ridge and the zone of polarizing activity by John W. Saunders.[45]

In 2006, scientists researching the ancestry of birds "turned on" a chicken recessive gene, talpid2, and found that the embryo jaws initiated formation of teeth, like those found in ancient bird fossils. John Fallon, the overseer of the project, stated that chickens have "...retained the ability to make teeth, under certain conditions... ."[46]

Genetics and genomics

 
Mottle gene

Given its eminent role in farming, meat production, but also research, the house chicken was the first bird genome to be sequenced.[47] At 1.21 Gb, the chicken genome is similarly sized compared to other birds, but smaller than nearly all mammals, such as the human genome (of 3.2 Gb).[48] The final gene set contained 26,640 genes (including noncoding genes and pseudogenes), with a total of 19,119 protein-coding genes in annotation release 103 (2017), a similar number of protein-coding genes as in the human genome.[49]

Physiology

Populations of chickens from high-altitude regions like Tibet have special physiological adaptations that result in a higher hatching rate in low oxygen environments. When eggs are placed in a hypoxic environment, chicken embryos from these populations express much more hemoglobin than embryos from other chicken populations. This hemoglobin also has a greater affinity for oxygen, allowing hemoglobin to bind to oxygen more readily.[50]

Pinopsins were originally discovered in the chicken pineal gland.[51]

Although all avians appear to have lost TLR9, artificial immunity against bacterial pathogens has been induced in neonatal chicks by Taghavi et al. 2008 using tailored oligodeoxynucleotides.[52]

Origin and dispersal

Origin

Galliformes, the order of bird that chickens belong to, is directly linked to the survival of birds when all other dinosaurs went extinct. Water or ground-dwelling fowl, similar to modern partridges, survived the Cretaceous–Paleogene extinction event that killed all tree-dwelling birds and dinosaurs.[53] Some of these evolved into the modern galliformes, of which domesticated chickens are a main model. They are descended primarily from the red junglefowl (Gallus gallus) and are scientifically classified as the same species.[54] As such, domesticated chickens can and do freely interbreed with populations of red junglefowl.[54] Subsequent hybridization of the domestic chicken with grey junglefowl, Sri Lankan junglefowl and green junglefowl occurred;[55] a gene for yellow skin, for instance, was incorporated into domestic birds through hybridization with the grey junglefowl (G. sonneratii).[56] In a study published in 2020, it was found that chickens shared between 71–79% of their genome with red junglefowl, with the period of domestication dated to 8,000 years ago.[55]

Domestication

According to one early study, a single domestication event of the red junglefowl in present-day Thailand gave rise to the modern chicken with minor transitions separating the modern breeds.[57] The red junglefowl is well adapted to take advantage of the vast quantities of seed produced during the end of the multi-decade bamboo seeding cycle, to boost its own reproduction.[58] In domesticating the chicken, humans took advantage of this predisposition for prolific reproduction of the red junglefowl when exposed to large amounts of food.[59]

Exactly when and where the chicken was domesticated remains a controversial issue. Genomic studies estimate that the chicken was domesticated 8,000 years ago[55] in Southeast Asia and spread to China and India 2,000 to 3,000 years later. Archaeological evidence supports domestic chickens in Southeast Asia well before 6000 BC, China by 6000 BC and India by 2000 BC.[55][60][61] A landmark 2020 Nature study that fully sequenced 863 chickens across the world suggests that all domestic chickens originate from a single domestication event of red junglefowl whose present-day distribution is predominantly in southwestern China, northern Thailand and Myanmar. These domesticated chickens spread across Southeast and South Asia where they interbred with local wild species of junglefowl, forming genetically and geographically distinct groups. Analysis of the most popular commercial breed shows that the White Leghorn breed possesses a mosaic of divergent ancestries inherited from subspecies of red junglefowl.[62][63][64]

Dispersal

 
Map showing the prehistoric introduction of domesticated chickens into Oceania from the Philippines via the Neolithic Austronesian expansion (starting at c. 4000 BP), inferred from genetic markers on ancient and modern chicken DNA (Thomson et al., 2014)[65]

A word for the domestic chicken (*manuk) is part of the reconstructed Proto-Austronesian language, indicating they were domesticated by the Austronesian peoples since ancient times. Chickens, together with dogs and pigs, were carried throughout the entire range of the prehistoric Austronesian maritime migrations to Island Southeast Asia, Micronesia, Island Melanesia, Polynesia, and Madagascar, starting from at least 3000 BC from Taiwan.[65][66][67][68] These chickens might have been introduced during pre-Columbian times to South America via Polynesian seafarers, but evidence for this is still putative.[69]

Middle Eastern chicken remains go back to a little earlier than 2000 BC in Syria. They reached Egypt for purposes of cockfighting about 1400 BC and became widely bred in Egypt around 300 BC.[70] Phoenicians spread chickens along the Mediterranean coasts as far as Iberia. During the Hellenistic period (4th–2nd centuries BC), in the southern Levant, chickens began to be widely domesticated for food.[71] This change occurred at least 100 years before domestication of chickens spread to Europe.

The first pictures of chickens in Europe are found on Corinthian pottery of the 7th century BC.[72][73]

Chickens reached Europe c. 100 BC.[74] Breeding increased under the Roman Empire and reduced by the Middle Ages.[70] Genetic sequencing of chicken bones from archaeological sites in Europe revealed that in the High Middle Ages chickens became less aggressive and began to lay eggs earlier in the breeding season.[75]

Three possible routes of introduction into Africa around the early first millennium AD could have been through the Egyptian Nile Valley, the East Africa Roman-Greek or Indian trade, or from Carthage and the Berbers, across the Sahara. The earliest known remains are from Mali, Nubia, East Coast, and South Africa and date back to the middle of the first millennium AD.[70]

Domestic chicken in the Americas before Western contact is still an ongoing discussion, but blue-egged chickens, found only in the Americas and Asia, suggest an Asian origin for early American chickens.[70] A lack of data from Thailand, Russia, the Indian subcontinent, Southeast Asia and Sub-Saharan Africa makes it difficult to lay out a clear map of the spread of chickens in these areas; better description and genetic analysis of local breeds threatened by extinction may also help with research into this area.[70]

South America

An unusual variety of chicken that has its origins in South America is the Araucana, bred in southern Chile by the Mapuche people. Araucanas lay blue-green eggs. Additionally, some Araucanas are tailless, and some have tufts of feathers around their ears. It has long been suggested that they pre-date the arrival of European chickens brought by the Spanish and are evidence of pre-Columbian trans-Pacific contacts between Asian or Pacific Oceanic peoples, particularly the Polynesians, and South America. In 2007, an international team of researchers reported the results of their analysis of chicken bones found on the Arauco Peninsula in south-central Chile. Radiocarbon dating suggested that the chickens were pre-Columbian, and DNA analysis showed that they were related to prehistoric populations of chickens in Polynesia.[76] These results appeared to confirm that the chickens came from Polynesia and that there were transpacific contacts between Polynesia and South America before Columbus' arrival in the Americas.[77][78]

However, a later report looking at the same specimens concluded:

A published, apparently pre-Columbian, Chilean specimen and six pre-European Polynesian specimens also cluster with the same European/Indian subcontinental/Southeast Asian sequences, providing no support for a Polynesian introduction of chickens to South America. In contrast, sequences from two archaeological sites on Easter Island group with an uncommon haplogroup from Indonesia, Japan, and China and may represent a genetic signature of an early Polynesian dispersal. Modeling of the potential marine carbon contribution to the Chilean archaeological specimen casts further doubt on claims for pre-Columbian chickens, and definitive proof will require further analyses of ancient DNA sequences and radiocarbon and stable isotope data from archaeological excavations within both Chile and Polynesia.[79]

The debate for and against a Polynesian origin for South American chickens continued with this 2014 paper and subsequent responses in PNAS.[80]

Use by humans

Farming

Main articles: Poultry farming and Chicken as food
 
A former battery hen, five days after release. Note the pale comb – the comb may be an indicator of health or vigor.[81]

More than 50 billion chickens are reared annually as a source of meat and eggs.[82] In the United States alone, more than 8 billion chickens are slaughtered each year for meat,[83] and more than 300 million chickens are reared for egg production.[84] The vast majority of poultry is raised in factory farms. According to the Worldwatch Institute, 74% of the world's poultry meat and 68% of eggs are produced this way.[85] An alternative to intensive poultry farming is free-range farming.

Friction between these two main methods has led to long-term issues of ethical consumerism. Opponents of intensive farming argue that it harms the environment, creates human health risks and is inhumane.[86] Advocates of intensive farming say that their highly efficient systems save land and food resources owing to increased productivity, and that the animals are looked after in state-of-the-art environmentally controlled facilities.[87]

Reared for meat

 
A commercial chicken house with open sides raising broiler pullets for meat

Chickens farmed for meat are called broilers. Chickens will naturally live for six or more years, but broiler breeds typically take less than six weeks to reach slaughter size.[88] A free range or organic broiler will usually be slaughtered at about 14 weeks of age.

Reared for eggs

Main article: Egg as food

Chickens farmed primarily for eggs are called layer hens. In total, the UK alone consumes more than 34 million eggs per day.[89] Some hen breeds can produce over 300 eggs per year, with the highest authenticated rate of egg laying being 371 eggs in 364 days.[90] After 12 months of laying, the commercial hen's egg-laying ability starts to decline to the point where the flock is commercially unviable. Hens, particularly from battery cage systems, are sometimes infirm or have lost a significant amount of their feathers, and their life expectancy has been reduced from around seven years to less than two years.[91]

In the UK and Europe, laying hens are then slaughtered and used in processed foods or sold as 'soup hens'.[91] In some other countries, flocks are sometimes force moulted rather than being slaughtered to re-invigorate egg-laying. This involves complete withdrawal of food (and sometimes water) for 7–14 days[92] or sufficiently long to cause a body weight loss of 25 to 35%,[93] or up to 28 days under experimental conditions.[94] This stimulates the hen to lose her feathers but also re-invigorates egg-production. Some flocks may be force-moulted several times. In 2003, more than 75% of all flocks were moulted in the US.[95]

As pets

 
Woman with rooster

Keeping chickens as pets became increasingly popular in the 2000s[96] among urban and suburban residents.[97] Many people obtain chickens for their egg production but often name them and treat them as any other pet like cats or dogs. Chickens provide companionship and have individual personalities. While many do not cuddle much, they will eat from one's hand, jump onto one's lap, respond to and follow their handlers, as well as show affection.[98][99]

Chickens are social, inquisitive, intelligent[100] birds, and many find their behaviour entertaining.[101] Certain breeds, such as silkies and many bantam varieties, are generally docile and are often recommended as good pets around children with disabilities.[102] Many people feed chickens in part with kitchen food scraps.

 
Backyard heritage chickens eating kitchen food scraps.

[103]

Cockfighting

 
Two cocks fighting

A cockfight is a contest held in a ring called a cockpit between two cocks known as gamecocks. This term, denoting a cock kept for game, sport, pastime or entertainment, appears in 1646,[104] after "cock of the game" used by George Wilson in the earliest known book on the secular sport, The Commendation of Cocks and Cock Fighting of 1607. Gamecocks are not typical farm chickens. The cocks are specially bred and trained for increased stamina and strength. The comb and wattle are removed from a young gamecock because if left intact, they would be a disadvantage during a match. This process is called dubbing. Sometimes the cocks are given drugs to increase their stamina or thicken their blood, which increases their chances of winning. Cockfighting is considered a traditional sporting event by some but an example of animal cruelty by others and is therefore outlawed in most countries.[105] Usually wagers are made on the outcome of the match, with the survivor or last bird standing declared winner.

Cocks possess congenital aggression toward other cocks to contest for females. Studies suggest that cockfights have existed even up to the Indus Valley civilisation as a pastime.[106] Today it is commonly associated with religious worship, pastime, and gambling in Asian and some South American countries. While not all fights are to the death, most use metal spurs as a weapon attached above or below the chicken's own spur, which typically results in death in one or both cocks. If chickens are in practice, owners place gloves on the spurs to prevent injuries.

Artificial incubation

Incubation can occur artificially in machines that provide the correct, controlled environment for the developing chick.[107][108] The average incubation period for chickens is 21 days, but the duration depends on the temperature and humidity in the incubator. Temperature regulation is the most critical factor for a successful hatch. Variations of more than 1 °C (1.8 °F) from the optimum temperature of 37.5 °C (99.5 °F) will reduce hatch rates. Humidity is also important because the rate at which eggs lose water by evaporation depends on the ambient relative humidity. Evaporation can be assessed by candling, to view the size of the air sac, or by measuring weight loss. Relative humidity should be increased to around 70% in the last three days of incubation to keep the membrane around the hatching chick from drying out after the chick cracks the shell. Lower humidity is usual in the first 18 days to ensure adequate evaporation.

The position of the eggs in the incubator can also influence hatch rates. For best results, eggs should be placed with the pointed ends down and turned regularly (at least three times per day) until one to three days before hatching. If the eggs are not turned, the embryo inside may stick to the shell and may hatch with physical defects. Adequate ventilation is necessary to provide the embryo with oxygen. Older eggs require increased ventilation.

Many commercial incubators are industrial-sized with shelves holding tens of thousands of eggs at a time, with rotation of the eggs a fully automated process. Home incubators are boxes holding from 6 to 75 eggs.

Diseases and ailments

See also: Poultry disease

Chickens are susceptible to several parasites, including lice, mites, ticks, fleas, and intestinal worms, as well as other diseases. Despite the name, they are not affected by chickenpox, which is generally restricted to humans.[109] Chickens can carry and transmit salmonella in their dander and feces. In the United States, the Centers for Disease Control and Prevention advise against bringing them indoors or letting small children handle them.[110][111]

Some of the diseases that can affect chickens are shown below:

Name Common name Cause
Aspergillosis Aspergillus fungi
Avian influenza bird flu virus
Histomoniasis blackhead disease Histomonas meleagridis
Botulism paralysis Clostridium botulinum toxin
Cage layer fatigue mineral deficiency, lack of physical exercise
Campylobacteriosis tissue injury in the gut
Coccidiosis Coccidia
Colds virus
Crop bound[112] improper feeding
Dermanyssus gallinae red mite parasite
Egg binding oversized egg
Erysipelas Streptococcus bacteria
Fatty liver hemorrhagic syndrome high-energy food
Fowl cholera Pasteurella multocida
Fowlpox Fowlpox virus
Fowl typhoid bacteria
Avian infectious laryngotracheitis LT Gallid alphaherpesvirus 1
Gapeworm Syngamus trachea worms
Infectious bronchitis[113] Infectious bronchitis virus
Infectious bursal disease Gumboro infectious bursal disease virus
Infectious coryza in chickens Avibacterium paragallinarum
Lymphoid leukosis Avian sarcoma leukosis virus
Marek's disease Gallid alphaherpesvirus 2
Moniliasis yeast infection
or thrush 		Candida fungi
Mycoplasma bacteria
Newcastle disease Avian avulavirus 1
Necrotic enteritis[114] bacteria
Omphalitis Mushy chick disease[115] bacteria
Peritonitis[116] infection in abdomen from egg yolk
Psittacosis Chlamydia psittaci
Pullorum Salmonella bacteria
Scaly leg Knemidokoptes mutans
Squamous cell carcinoma cancer
Tibial dyschondroplasia speed growing
Toxoplasmosis Toxoplasma gondii
Trichomoniasis roup Trichomonas gallinae
Ulcerative enteritis[117] bacteria
Ulcerative pododermatitis bumblefoot bacteria

Impacts of climate change

This section is an excerpt from Effects of climate change on livestock § Poultry.[edit]
 
Photo of an egg farm in New England, taken around 2009.

It is believed that the thermal comfort zone for poultry is in the 18–25 °C (64–77 °F) range. Some papers describe 26–35 °C (79–95 °F) as the "critical zone" for heat stress, but others report that due to acclimatization, birds in the tropical countries do not begin to experience heat stress until 32 °C (90 °F). There is wider agreement that temperatures greater than 35 °C (95 °F) and 47 °C (117 °F) form "upper critical" and lethal zones, respectively.[118] Average daily temperatures of around 33 °C (91 °F) are known to interfere with feeding in both broilers and egg hens, as well as lower their immune response, with outcomes such as reduced weight gain/egg production or greater incidence of salmonella infections, footpad dermatitis or meningitis. Persistent heat stress leads to oxidative stress in tissues, and harvested white meat ends up with a lower proportion of essential compounds like vitamin E, lutein and zeaxanthin, yet an increase in glucose and cholesterol. Multiple studies show that dietary supplementation with chromium can help to relieve these issues due to its antioxidative properties, particularly in combination with zinc or herbs like wood sorrel.[119][120][121][122][123][124] Resveratrol is another popular antioxidant administered to poultry for these reasons.[125] Though the effect of supplementation is limited, it is much cheaper than interventions to improve cooling or simply stock fewer birds, and so remains popular.[126] While the majority of literature on poultry heat stress and dietary supplementation focuses on chickens, similar findings were seen in Japanese quails, which eat less and gain less weight, suffer reduced fertility and hatch eggs of worse quality under heat stress, and also seem to benefit from mineral supplementation.[127][128][129]

Around 2003 it was estimated that the poultry industry in the United States already lost up to $165 million annually due to heat stress at the time.[118] One paper estimated that if global warming reaches 2.5 °C (4.5 °F), then the cost of rearing broilers in Brazil increases by 35.8% at the least modernized farms and by 42.3% at farms with the medium level of technology used in livestock housing, while they increase the least at farms with the most advanced cooling technologies. On the contrary, if the warming is kept to 1.5 °C (2.7 °F), costs at moderately modernized farms increase the least, by 12.5%, followed by the most modernized farms with a 19.9% increase, and the least technological farms seeing the greatest increase.[130]

Gallery

 
Wikimedia Commons has media related to Category:Chickens.
 
Wikimedia Commons has media related to Category:Gallus gallus.

Notes

  1. ^ The surgical and chemical castration of chickens is now illegal in some parts of the world.

References

  1. ^
    • Lawal, Raman Akinyanju; Martin, Simon H.; Vanmechelen, Koen; Vereijken, Addie; Silva, Pradeepa; Al-Atiyat, Raed Mahmoud; Aljumaah, Riyadh Salah; Mwacharo, Joram M.; Wu, Dong-Dong; Zhang, Ya-Ping; Hocking, Paul M.; Smith, Jacqueline; Wragg, David; Hanotte, Olivier (February 12, 2020). "The wild species genome ancestry of domestic chickens". BMC Biology. BioMed Central. 18 (1): 13. doi:10.1186/s12915-020-0738-1. ISSN 1741-7007. PMC 7014787. PMID 32050971. S2CID 211081254.
    • Tiley, George P.; Poelstra, Jelmer W.; dos Reis, Mario; Yang, Ziheng; Yoder, Anne D. (2020). "Molecular Clocks without Rocks: New Solutions for Old Problems". Trends in Genetics. Cell Press. 36 (11): 845–856. doi:10.1016/j.tig.2020.06.002. ISSN 0168-9525. PMID 32709458. S2CID 220747034. from the original on June 11, 2022. Retrieved April 11, 2022.
    • Tregaskes, Clive A.; Kaufman, Jim (2021). "Chickens as a simple system for scientific discovery: The example of the MHC". Molecular Immunology. Elsevier. 135: 12–20. doi:10.1016/j.molimm.2021.03.019. ISSN 0161-5890. PMC 7611830. PMID 33845329. S2CID 233223219. EuroPMC manus. 136199.
    • Lawal, R. A.; Hanotte, O. (May 31, 2021). "Domestic chicken diversity: Origin, distribution, and adaptation". Animal Genetics. International Foundation for Animal Genetics (Wiley). 52 (4): 385–394. doi:10.1111/age.13091. ISSN 0268-9146. PMID 34060099. S2CID 235268576.
    • Siegel, Paul B.; Honaker, Christa F.; Scanes, Colin G. (2022). "Domestication of poultry". Sturkie's Avian Physiology. Elsevier. pp. 109–120. doi:10.1016/b978-0-12-819770-7.00026-8. ISBN 978-0-12-819770-7. S2CID 244084328.
    • Eda, Masaki (May 1, 2021). "Origin of the domestic chicken from modern biological and zooarchaeological approaches". Animal Frontiers. American Society of Animal Science (OUP). 11 (3): 52–61. doi:10.1093/af/vfab016. ISSN 2160-6056. PMC 8214436. PMID 34158989. S2CID 235593797.
    • van Grouw, Hein; Dekkers, Wim (September 21, 2020). "Temminck's Gallus giganteus; a gigantic obstacle to Darwin's theory of domesticated fowl origin?". Bulletin of the British Ornithologists' Club. British Ornithologists' Club. 140 (3). doi:10.25226/bboc.v140i3.2020.a5. ISSN 0007-1595. S2CID 221823963.
  2. ^ "Number of chickens worldwide from 1990 to 2018". Statista. from the original on November 27, 2020. Retrieved February 23, 2020.
  3. ^ Xiang, Hai; Gao, Jianqiang; Yu, Baoquan; Zhou, Hui; Cai, Dawei; Zhang, Youwen; Chen, Xiaoyong; Wang, Xi; Hofreiter, Michael; Zhao, Xingbo (December 9, 2014). "Early Holocene chicken domestication in northern China". Proceedings of the National Academy of Sciences. 111 (49): 17564–17569. Bibcode:2014PNAS..11117564X. doi:10.1073/pnas.1411882111. PMC 4267363. PMID 25422439.
  4. ^ Carter, Howard (April 1923). "An Ostracon Depicting a Red Jungle-Fowl (The Earliest Known Drawing of the Domestic Cock)". The Journal of Egyptian Archaeology. 9 (1/2): 1–4. doi:10.2307/3853489. JSTOR 3853489.
  5. ^ Pritchard, Earl H. "The Asiatic Campaigns of Thutmose III". Ancient Near East Texts related to the Old Testament. p. 240.
  6. ^ Roehrig, Catharine H.; Dreyfus, Renée; Keller, Cathleen A. (2005). Hatshepsut: From Queen to Pharaoh. New York: Metropolitan Museum of Art. p. 268. ISBN 978-1-58839-173-5. Retrieved November 26, 2015.
  7. ^ Toussaint-Samat, Maguelonne (2009). "11: The History of Poultry". The History of Food. Translated by Bell, Anthea (revised ed.). Blackwell. p. 306. ISBN 978-0631177418.
  8. ^ Perry-Gal, Lee; Erlich, Adi; Gilboa, Ayelet; Bar-Oz, Guy (August 11, 2015). "Earliest economic exploitation of chicken outside East Asia: Evidence from the Hellenistic Southern Levant". Proceedings of the National Academy of Sciences. 112 (32): 9849–9854. Bibcode:2015PNAS..112.9849P. doi:10.1073/pnas.1504236112. PMC 4538678. PMID 26195775.
  9. ^ "Cock". Cambridge Dictionary. from the original on September 7, 2015. Retrieved March 4, 2021.
  10. ^ "Hen". Cambridge Dictionary. from the original on September 7, 2015. Retrieved March 4, 2021.
  11. ^ "Definition of biddy | Dictionary.com". www.dictionary.com. from the original on May 7, 2021. Retrieved May 7, 2021.
  12. ^ "Biddy definition and meaning | Collins English Dictionary". www.collinsdictionary.com. from the original on May 7, 2021. Retrieved May 7, 2021.
  13. ^ "Chick". Cambridge Dictionary. from the original on September 7, 2015.
  14. ^ "Chook". Cambridge Dictionary. from the original on September 7, 2015. Retrieved March 4, 2021.
  15. ^ Cockerel. Dictionary.reference.com. from the original on March 7, 2016. Retrieved August 29, 2010.
  16. ^ Richardson, H. D. (1847). Domestic fowl: their natural history, breeding, rearing, and general management. from the original on June 11, 2022. Retrieved March 30, 2022.
  17. ^ Pullet. Dictionary.reference.com. from the original on November 9, 2010. Retrieved August 29, 2010.
  18. ^ "Overview of the Poultry Industry" (PDF). Overview of the Poultry Industry. Missouri Department of Elementary and Secondary Education. p. 8. (PDF) from the original on October 23, 2020.
  19. ^ Berhardt, Clyde E. B. (1986). I Remember: Eighty Years of Black Entertainment, Big Bands. Philadelphia: University of Pennsylvania Press. p. 153. ISBN 978-0-8122-8018-0. OCLC 12805260.
  20. ^ "Chicken". Merriam Webster Dictionary. from the original on August 21, 2008. Retrieved March 4, 2021.
  21. ^ Stevens, Lewis, Genetics and evolution of the domestic fowl, p 1 and throughout, 1991, Cambridge University Press, google books
  22. ^ "Definition of ROOSTER". www.merriam-webster.com. from the original on April 22, 2021. Retrieved March 6, 2021.
  23. ^ Hugh Rawson July 1, 2017, at the Wayback Machine "Why Do We Say...? Rooster", American Heritage, August–September 2006.
  24. ^ Online Etymology Dictionary November 11, 2020, at the Wayback Machine Entry for rooster (n.), May 2019
  25. ^ "Definition of ROOST". Collins English Dictionary. from the original on May 1, 2021. Retrieved October 16, 2021.
  26. ^ . Ideas-4-pets.co.uk. 2003. Archived from the original on June 25, 2015. Retrieved August 13, 2008.
  27. ^ D Lines (July 27, 2013). "Chicken Kills Rattlesnake". YouTube. Archived from the original on December 11, 2021. Retrieved March 13, 2019.
  28. ^ Gerard P.Worrell AKA "Farmer Jerry". "Frequently asked questions about chickens & eggs". Gworrell.freeyellow.com. from the original on September 16, 2008. Retrieved August 13, 2008.
  29. ^ . Ruleworks.co.uk. Archived from the original on November 28, 2010. Retrieved August 29, 2010.
  30. ^ Smith, Jamon (August 6, 2006). "World's oldest chicken starred in magic shows, was on 'Tonight Show'". Tuscaloosa News. Alabama, USA. from the original on February 20, 2019. Retrieved May 18, 2020.
  31. ^ Ying Guo, Xiaorong Gu, Zheya Sheng, Yanqiang Wang, Chenglong Luo, Ranran Liu, Hao Qu, Dingming Shu, Jie Wen, Richard P. M. A. Crooijmans, Örjan Carlborg, Yiqiang Zhao, Xiaoxiang Hu, Ning Li (2016). A Complex Structural Variation on Chromosome 27 Leads to the Ectopic Expression of HOXB8 and the Muffs and Beard Phenotype in Chickens November 5, 2021, at the Wayback Machine. PLoS Genetics. 12 (6): e1006071. doi:10.1371/journal.pgen.1006071.
  32. ^ "Chickens team up to 'peck fox to death'". The Independent. March 13, 2019. from the original on March 15, 2019. Retrieved March 13, 2019.
  33. ^ "Chickens 'gang up' to kill fox". Bbc.co.uk. March 13, 2019. from the original on March 14, 2019. Retrieved March 13, 2019.
  34. ^ AFP (March 12, 2019). "Chickens 'teamed up to kill fox' at Brittany farming school". Theguardian.com. from the original on March 13, 2019. Retrieved March 13, 2019.
  35. ^ a b "Why Do Chickens Puff up Their Feathers? I 4 Reasons Explained". August 8, 2020. from the original on June 18, 2021. Retrieved June 16, 2021.
  36. ^ "Top cock: Roosters crow in pecking order". from the original on January 15, 2018. Retrieved January 14, 2018.
  37. ^ Evans, Christopher S.; Evans, Linda; Marler, Peter (July 1993). "On the meaning of alarm calls: functional reference in an avian vocal system". Animal Behaviour. 46 (1): 23–38. doi:10.1006/anbe.1993.1158. S2CID 53165305.
  38. ^ Cock crowing contest recognised as National Heritage in Belgium November 23, 2020, at the Wayback Machine Stefaan De Groote, Het Nieuwsblad, 27. June 2011 (in Dutch). Accessed October 2015
  39. ^ a b c Grandin, Temple; Johnson, Catherine (2005). Animals in Translation. New York City: Scribner. pp. 69–71. ISBN 978-0-7432-4769-6.
  40. ^ Cheng, Kimberly M.; Burns, Jeffrey T. (August 1988). "Dominance Relationship and Mating Behavior of Domestic Cocks: A Model to Study Mate-Guarding and Sperm Competition in Birds". The Condor. 90 (3): 697–704. doi:10.2307/1368360. JSTOR 1368360.
  41. ^ Sherwin, C.M.; Nicol, C.J. (1993). "Factors influencing floor-laying by hens in modified cages". Applied Animal Behaviour Science. 36 (2–3): 211–222. doi:10.1016/0168-1591(93)90011-d.
  42. ^ Ali, A.; Cheng, K.M. (1985). "Early egg production in genetically blind (rc/rc) chickens in comparison with sighted (Rc+/rc) controls". Poultry Science. 64 (5): 789–794. doi:10.3382/ps.0640789. PMID 4001066.
  43. ^ Briskie, J. V.; R. Montgomerie (1997). "Sexual Selection and the Intromittent Organ of Birds". Journal of Avian Biology. 28 (1): 73–86. doi:10.2307/3677097. JSTOR 3677097.
  44. ^ Bain, M. M.; Nys, Y.; Dunn, I.C. (May 3, 2016). "Increasing persistency in lay and stabilising egg quality in longer laying cycles. What are the challenges?". British Poultry Science. Taylor & Francis. 57 (3): 330–338. doi:10.1080/00071668.2016.1161727. ISSN 0007-1668. PMC 4940894. PMID 26982003. S2CID 17842329.
  45. ^ Young, John J.; Tabin, Clifford J. (September 2017). "Saunders's framework for understanding limb development as a platform for investigating limb evolution". Developmental Biology. 429 (2): 401–408. doi:10.1016/j.ydbio.2016.11.005. PMC 5426996. PMID 27840200.
  46. ^ Scientists Find Chickens Retain Ancient Ability to Grow Teeth June 20, 2008, at the Wayback Machine Ammu Kannampilly, ABC News, February 27, 2006. Retrieved October 1, 2007.
  47. ^ International Chicken Genome Sequencing Consortium (December 9, 2004). "Sequence and comparative analysis of the chicken genome provide unique perspectives on vertebrate evolution". Nature. 432 (7018): 695–716. Bibcode:2004Natur.432..695C. doi:10.1038/nature03154. PMID 15592404.
  48. ^ Gregory, T. Ryan (September 2005). "Synergy between sequence and size in Large-scale genomics". Nature Reviews Genetics. 6 (9): 699–708. doi:10.1038/nrg1674.
  49. ^ Warren, Wesley C.; Hillier, LaDeana W.; Tomlinson, Chad; Minx, Patrick; Kremitzki, Milinn; Graves, Tina; Markovic, Chris; Bouk, Nathan; Pruitt, Kim D.; Thibaud-Nissen, Francoise; Schneider, Valerie; Mansour, Tamer A.; Brown, C. Titus; Zimin, Aleksey; Hawken, Rachel; Abrahamsen, Mitch; Pyrkosz, Alexis B.; Morisson, Mireille; Fillon, Valerie; Vignal, Alain; Chow, William; Howe, Kerstin; Fulton, Janet E.; Miller, Marcia M.; Lovell, Peter; Mello, Claudio V.; Wirthlin, Morgan; Mason, Andrew S.; Kuo, Richard; Burt, David W.; Dodgson, Jerry B.; Cheng, Hans H. (January 2017). "A New Chicken Genome Assembly Provides Insight into Avian Genome Structure". G3. 7 (1): 109–117. doi:10.1534/g3.116.035923. PMC 5217101. PMID 27852011.
  50. ^ Zhang, H.; Wang, X.T.; Chamba, Y.; Ling, Y.; Wu, C.X. (October 2008). "Influences of Hypoxia on Hatching Performance in Chickens with Different Genetic Adaptation to High Altitude". Poultry Science. 87 (10): 2112–2116. doi:10.3382/ps.2008-00122. ISSN 0032-5791. PMID 18809874.
  51. ^ Nakane, Yusuke; Yoshimura, Takashi (February 15, 2019). "Photoperiodic Regulation of Reproduction in Vertebrates". Annual Review of Animal Biosciences. Annual Reviews. 7 (1): 173–194. doi:10.1146/annurev-animal-020518-115216. ISSN 2165-8102. PMID 30332291. S2CID 52984435.
  52. ^ Brownlie, Robert; Allan, Brenda (September 1, 2010). "Avian toll-like receptors". Cell and Tissue Research. Springer. 343 (1): 121–130. doi:10.1007/s00441-010-1026-0. ISSN 0302-766X. PMID 20809414. S2CID 2877905.
  53. ^ Pennisi, Elizabeth (May 24, 2018). "Quaillike creatures were the only birds to survive the dinosaur-killing asteroid impact". Science. doi:10.1126/science.aau2802.
  54. ^ a b Wong, G. K.; Liu, B.; Wang, J.; Zhang, Y.; Yang, X.; Zhang, Z.; Meng, Q.; Zhou, J.; Li, D.; Zhang, J.; Ni, P.; Li, S.; Ran, L.; Li, H.; Zhang, J.; Li, R.; Li, S.; Zheng, H.; Lin, W.; Li, G.; Wang, X.; Zhao, W.; Li, J.; Ye, C.; Dai, M.; Ruan, J.; Zhou, Y.; Li, Y.; He, X.; et al. (December 9, 2004). "A genetic variation map for chicken with 2.8 million single nucleotide polymorphisms". Nature. 432 (7018): 717–722. Bibcode:2004Natur.432..717B. doi:10.1038/nature03156. PMC 2263125. PMID 15592405.
  55. ^ a b c d Lawal, Raman Akinyanju; Martin, Simon H.; Vanmechelen, Koen; Vereijken, Addie; Silva, Pradeepa; Al-Atiyat, Raed Mahmoud; Aljumaah, Riyadh Salah; Mwacharo, Joram M.; Wu, Dong-Dong; Zhang, Ya-Ping; Hocking, Paul M.; Smith, Jacqueline; Wragg, David; Hanotte, Olivier (December 2020). "The wild species genome ancestry of domestic chickens". BMC Biology. 18 (1): 13. doi:10.1186/s12915-020-0738-1. PMC 7014787. PMID 32050971.
  56. ^ Eriksson, Jonas; Larson, Greger; Gunnarsson, Ulrika; Bed'hom, Bertrand; Tixier-Boichard, Michele; Strömstedt, Lina; Wright, Dominic; Jungerius, Annemieke; Vereijken, Addie; Randi, Ettore; Jensen, Per; Andersson, Leif (February 29, 2008). "Identification of the Yellow Skin Gene Reveals a Hybrid Origin of the Domestic Chicken". PLOS Genetics. 4 (2): e1000010. doi:10.1371/journal.pgen.1000010. PMC 2265484. PMID 18454198.
  57. ^ Fumihito, A; Miyake, T; Sumi, S; Takada, M; Ohno, S; Kondo, N (December 20, 1994), "One subspecies of the red junglefowl (Gallus gallus gallus) suffices as the matriarchic ancestor of all domestic breeds", PNAS, 91 (26): 12505–12509, Bibcode:1994PNAS...9112505F, doi:10.1073/pnas.91.26.12505, PMC 45467, PMID 7809067
  58. ^ King, Rick (February 24, 2009), "Rat Attack", NOVA and National Geographic Television, from the original on August 23, 2017, retrieved August 25, 2017
  59. ^ King, Rick (February 1, 2009), "Plant vs. Predator", NOVA, from the original on August 21, 2017, retrieved August 25, 2017
  60. ^ West, B.; Zhou, B.X. (1988). "Did chickens go north? New evidence for domestication". J. Archaeol. Sci. 14 (5): 515–533. doi:10.1016/0305-4403(88)90080-5.
  61. ^ Al-Nasser, A.; Al-Khalaifa, H.; Al-Saffar, A.; Khalil, F.; Albahouh, M.; Ragheb, G.; Al-Haddad, A.; Mashaly, M. (June 1, 2007). "Overview of chicken taxonomy and domestication". World's Poultry Science Journal. 63 (2): 285–300. doi:10.1017/S004393390700147X. S2CID 86734013.
  62. ^ Wang, Ming-Shan; et al. (2020). "863 genomes reveal the origin and domestication of chicken". Cell Research. 30 (8): 693–701. doi:10.1038/s41422-020-0349-y. PMC 7395088. PMID 32581344. S2CID 220050312.
  63. ^ Liu, Yi-Ping; Wu, Gui-Sheng; Yao, Yong-Gang; Miao, Yong-Wang; Luikart, Gordon; Baig, Mumtaz; Beja-Pereira, Albano; Ding, Zhao-Li; Palanichamy, Malliya Gounder; Zhang, Ya-Ping (January 2006). "Multiple maternal origins of chickens: Out of the Asian jungles". Molecular Phylogenetics and Evolution. 38 (1): 12–19. doi:10.1016/j.ympev.2005.09.014. PMID 16275023.
  64. ^ Zeder, Melinda A.; Emshwiller, Eve; Smith, Bruce D.; Bradley, Daniel G. (March 2006). "Documenting domestication: the intersection of genetics and archaeology". Trends in Genetics. 22 (3): 139–155. doi:10.1016/j.tig.2006.01.007. PMID 16458995.
  65. ^ a b Thomson, Vicki A.; Lebrasseur, Ophélie; Austin, Jeremy J.; Hunt, Terry L.; Burney, David A.; Denham, Tim; Rawlence, Nicolas J.; Wood, Jamie R.; Gongora, Jaime; Girdland Flink, Linus; Linderholm, Anna; Dobney, Keith; Larson, Greger; Cooper, Alan (April 2014). "Using ancient DNA to study the origins and dispersal of ancestral Polynesian chickens across the Pacific". Proceedings of the National Academy of Sciences. 111 (13): 4826–4831. Bibcode:2014PNAS..111.4826T. doi:10.1073/pnas.1320412111. PMC 3977275. PMID 24639505.
  66. ^ Piper, Philip J. (2017). "The Origins and Arrival of the Earliest Domestic Animals in Mainland and Island Southeast Asia: A Developing Story of Complexity". In Piper, Philip J.; Matsumura, Hirofumi; Bulbeck, David (eds.). New Perspectives in Southeast Asian and Pacific Prehistory. terra australis. Vol. 45. ANU Press. ISBN 9781760460945. from the original on November 28, 2022. Retrieved May 5, 2023.
  67. ^ Meleisea, Malama (March 25, 2004). The Cambridge History of the Pacific Islanders. Cambridge University Press. p. 56. ISBN 9780521003544. from the original on September 13, 2016. Retrieved March 13, 2019 – via Google Books.
  68. ^ Crawford, Michael H. (March 13, 2019). Anthropological Genetics: Theory, Methods and Applications. Cambridge University Press. p. 411. ISBN 9780521546973. from the original on September 13, 2016. Retrieved March 13, 2019 – via Google Books.
  69. ^ Neumann, Scott (March 18, 2014). "Study: The Chicken Didn't Cross The Pacific To South America". The Two Way. NPR. from the original on May 5, 2023. Retrieved May 5, 2023.
  70. ^ a b c d e CHOF : The Cambridge History of Food, 2000, Cambridge University Press, vol.1, pp496-499
  71. ^ Perry-Gal, Lee; Erlich, Adi; Gilboa, Ayelet; Bar-Oz, Guy (August 11, 2015). "Earliest economic exploitation of chicken outside East Asia: Evidence from the Hellenistic Southern Levant". Proceedings of the National Academy of Sciences. 112 (32): 9849–9854. Bibcode:2015PNAS..112.9849P. doi:10.1073/pnas.1504236112. PMC 4538678. PMID 26195775.
  72. ^ Karayanis, Dean; Karayanis, Catherine (March 13, 2019). Regional Greek Cooking. Hippocrene Books. p. 176. ISBN 9780781811460. from the original on September 13, 2016. Retrieved March 13, 2019 – via Google Books.
  73. ^ Chiffolo, Anthony F.; Hesse, Rayner W. (March 13, 2019). Cooking with the Bible: Biblical Food, Feasts, and Lore. Greenwood Publishing Group. p. 207. ISBN 9780313334108. from the original on September 13, 2016. Retrieved March 13, 2019 – via Google Books.
  74. ^ Perry-Gal, L.; Erlich, A.; Gilboa, A.; Bar-Oz, G. (2015). "Earliest economic exploitation of chicken outside East Asia: Evidence from the Hellenistic Southern Levant". Proceedings of the National Academy of Sciences of the United States of America. 112 (32): 9849–9854. Bibcode:2015PNAS..112.9849P. doi:10.1073/pnas.1504236112. PMC 4538678. PMID 26195775. "We further argue that the earliest secure evidence for economic exploitation of chickens in Europe dates to the first century B.C.E. and therefore is predated by the finds in the Southern Levant by at least a century."
  75. ^ Brown, Marley (September–October 2017). "Fast Food". Archaeology. 70 (5): 18. ISSN 0003-8113. from the original on July 25, 2019. Retrieved July 25, 2019.
  76. ^ Borrell, Brendan (June 1, 2007). "DNA reveals how the chicken crossed the sea". Nature. 447 (7145): 620–621. Bibcode:2007Natur.447R.620B. doi:10.1038/447620b. PMID 17554271. S2CID 4418786.
  77. ^ Storey, A. A.; Ramirez, J. M.; Quiroz, D.; Burley, D. V.; Addison, D. J.; Walter, R.; Anderson, A. J.; Hunt, T. L.; Athens, J. S.; Huynen, L.; Matisoo-Smith, E. A. (June 19, 2007). "Radiocarbon and DNA evidence for a pre-Columbian introduction of Polynesian chickens to Chile". Proceedings of the National Academy of Sciences. 104 (25): 10335–10339. Bibcode:2007PNAS..10410335S. doi:10.1073/pnas.0703993104. PMC 1965514. PMID 17556540.
  78. ^ Wilford, John Noble (June 5, 2007). "First Chickens in Americas Were Brought From Polynesia". The New York Times. from the original on June 7, 2007.
  79. ^ Gongora, Jaime; Rawlence, Nicolas J.; Mobegi, Victor A.; Jianlin, Han; Alcalde, Jose A.; Matus, Jose T.; Hanotte, Olivier; Moran, Chris; Austin, J.; Ulm, Sean; Anderson, Atholl; Larson, Greger; Cooper, Alan (2008). "Indo-European and Asian origins for Chilean and Pacific chickens revealed by mtDNA". PNAS. 105 (30): 10308–10313. Bibcode:2008PNAS..10510308G. doi:10.1073/pnas.0801991105. PMC 2492461. PMID 18663216.
  80. ^ Thomson, Vicki A.; Lebrasseur, Ophélie; Austin, Jeremy J.; Hunt, Terry L.; Burney, David A.; Denham, Tim; Rawlence, Nicolas J.; Wood, Jamie R.; Gongora, Jaime; Girdland Flink, Linus; Linderholm, Anna; Dobney, Keith; Larson, Greger; Cooper, Alan (April 1, 2014). "Using ancient DNA to study the origins and dispersal of ancestral Polynesian chickens across the Pacific". Proceedings of the National Academy of Sciences. 111 (13): 4826–4831. Bibcode:2014PNAS..111.4826T. doi:10.1073/pnas.1320412111. PMC 3977275. PMID 24639505.
  81. ^ Jones, E.K.M.; Prescott, N.B. (2000). "Visual cues used in the choice of mate by fowl and their potential importance for the breeder industry". World's Poultry Science Journal. 56 (2): 127–138. doi:10.1079/WPS20000010. S2CID 86481908.
  82. ^ "About chickens | Compassion in World Farming". Ciwf.org.uk. from the original on April 26, 2017. Retrieved April 25, 2017.
  83. ^ Fereira, John. "Poultry Slaughter Annual Summary". usda.mannlib.cornell.edu. from the original on April 26, 2017. Retrieved April 25, 2017.
  84. ^ Fereira, John. "Chickens and Eggs Annual Summary". usda.mannlib.cornell.edu. from the original on April 26, 2017. Retrieved April 25, 2017.
  85. ^ . World Watch Institute. Archived from the original on May 29, 2014. Retrieved May 29, 2014.
  86. ^ Ilea, Ramona Cristina (April 2009). "Intensive Livestock Farming: Global Trends, Increased Environmental Concerns, and Ethical Solutions". Journal of Agricultural and Environmental Ethics. 22 (2): 153–167. doi:10.1007/s10806-008-9136-3. S2CID 154306257.
  87. ^ Tilman, David; Cassman, Kenneth G.; Matson, Pamela A.; Naylor, Rosamond; Polasky, Stephen (August 2002). "Agricultural sustainability and intensive production practices". Nature. 418 (6898): 671–677. Bibcode:2002Natur.418..671T. doi:10.1038/nature01014. PMID 12167873. S2CID 3016610.
  88. ^ "Broiler Chickens Fact Sheet // Animals Australia". Animalsaustralia.org. from the original on July 12, 2010. Retrieved August 29, 2010.
  89. ^ "UK Egg Industry Data | Official Egg Info". Egginfo.co.uk. from the original on December 30, 2016. Retrieved April 25, 2017.
  90. ^ Glenday, Craig (April 26, 2011). Guinness World Records 2011. Mass Market Paperback. p. 286. ISBN 978-0440423102.
  91. ^ a b Browne, Anthony (March 10, 2002). "Ten weeks to live". The Guardian. London. from the original on May 16, 2008. Retrieved April 28, 2010.
  92. ^ Patwardhan, D.; King, A. (2011). "Review: feed withdrawal and non feed withdrawal moult". World's Poultry Science Journal. 67 (2): 253–268. doi:10.1017/s0043933911000286. S2CID 88353703.
  93. ^ Webster, A.B. (2003). "Physiology and behavior of the hen during induced moult". Poultry Science. 82 (6): 992–1002. doi:10.1093/ps/82.6.992. PMID 12817455.
  94. ^ Molino, A.B.; Garcia, E.A.; Berto, D.A.; Pelícia, K.; Silva, A.P.; Vercese, F. (2009). "The Effects of Alternative Forced-Molting Methods on The Performance and Egg Quality of Commercial Layers". Brazilian Journal of Poultry Science. 11 (2): 109–113. doi:10.1590/s1516-635x2009000200006.
  95. ^ Yousaf, M.; Chaudhry, A.S. (March 1, 2008). "History, changing scenarios and future strategies to induce moulting in laying hens" (PDF). World's Poultry Science Journal. 64 (1): 65–75. doi:10.1017/s0043933907001729. S2CID 34761543. (PDF) from the original on November 24, 2020. Retrieved October 23, 2020.
  96. ^ Fly, Colin (July 27, 2007). "Some homeowners find chickens all the rage". Chicago Tribune.[permanent dead link]
  97. ^ Pollack-Fusi, Mindy (December 16, 2004). "Cooped up in suburbia". Boston Globe. from the original on March 4, 2016. Retrieved June 4, 2020.
  98. ^ Kreilkamp, Ivan (November 25, 2020). "How Caring for Backyard Chickens Stretched My Emotional Muscles". The New York Times. from the original on November 25, 2020.
  99. ^ Boone, Lisa (August 27, 2017). "Chickens will become a beloved pet — just like the family dog". Los Angeles Times. from the original on April 2, 2019. Retrieved April 3, 2019.
  100. ^ Barras, Colin. . www.bbc.com. Archived from the original on June 5, 2021. Retrieved September 6, 2020.
  101. ^ United Poultry Concerns. "Providing a Good Home for Chickens". from the original on June 5, 2009. Retrieved May 4, 2009.
  102. ^ "Choosing Your Chickens". Clucks and Chooks. from the original on July 30, 2009.
  103. ^ "Is It Safe To Feed My Chickens Table Scraps?". The Happy Chicken Coop. October 21, 2021. from the original on October 4, 2022. Retrieved October 5, 2022.
  104. ^ gamecock – Merriam-Webster Online Dictionary August 18, 2017, at the Wayback Machine – first use of word – 1646
  105. ^ . CNN. November 26, 2002. Archived from the original on June 19, 2009. Retrieved August 17, 2009.
  106. ^ Sherman, David M. (2002). Tending Animals in the Global Village. Blackwell Publishing. 46. ISBN 0-683-18051-7.
  107. ^ Joe G. Berry. "Artificial Incubation". Oklahoma Cooperative Extension Service, Oklahoma State University. (PDF) from the original on June 4, 2010. Retrieved September 29, 2010.
  108. ^ Phillip J. Clauer. "Incubating Eggs" (PDF). Virginia Cooperative Extension Service, Virginia State University. (PDF) from the original on June 13, 2010. Retrieved October 1, 2010.
  109. ^ White, Tiffany M.; Gilden, Donald H.; Mahalingam, Ravi (October 2001). "An Animal Model of Varicella Virus Infection". Brain Pathology. 11 (4): 475–479. doi:10.1111/j.1750-3639.2001.tb00416.x. PMC 8098339. PMID 11556693. S2CID 26073177.
  110. ^ "Forget dogs and cats. The most pampered pets of the moment might be our backyard chickens". USA TODAY. from the original on April 3, 2019. Retrieved April 3, 2019.
  111. ^ CDC (March 18, 2019). "Keeping Backyard Poultry". Centers for Disease Control and Prevention. from the original on April 1, 2019. Retrieved April 3, 2019.
  112. ^ . Archived from the original on October 26, 2010.
  113. ^ "Infectious Bronchitis Virus: Classical and Variant Strains". from the original on October 5, 2021. Retrieved June 11, 2022.
  114. ^ . Archived from the original on December 16, 2010.
  115. ^ "Overview of Omphalitis in Poultry". Merck Veterinary Manual. from the original on January 13, 2017. Retrieved January 10, 2017.
  116. ^ "Clucks and Chooks: guide to keeping chickens". Henkeeping.co.uk. from the original on January 15, 2010. Retrieved October 26, 2009.
  117. ^ "Merck Veterinary Manual". from the original on March 11, 2007. Retrieved January 10, 2007.
  118. ^ a b Oladokun, Samson; Adewole, Deborah I. (October 1, 2022). "Biomarkers of heat stress and mechanism of heat stress response in Avian species: Current insights and future perspectives from poultry science". Journal of Thermal Biology. 110: 103332. doi:10.1016/j.jtherbio.2022.103332. PMID 36462852. S2CID 252361675.
  119. ^ Alhenaky, Alhanof; Abdelqader, Anas; Abuajamieh, Mohannad; Al-Fataftah, Abdur-Rahman (November 3, 2017). "The effect of heat stress on intestinal integrity and Salmonella invasion in broiler birds". Journal of Thermal Biology. 70 (Pt B): 9–14. doi:10.1016/j.jtherbio.2017.10.015. PMID 29108563.
  120. ^ Kuter, Eren; Cengiz, Özcan; Köksal, Bekir Hakan; Sevim, Ömer; Tatlı, Onur; Ahsan, Umair; Güven, Gülşen; Önol, Ahmet Gökhan; Bilgili, Sacit F. (December 28, 2022). "Litter quality and incidence and severity of footpad dermatitis in heat stressed broiler chickens fed supplemental zinc". Livestock Science. 267: 1491–1499. doi:10.1016/j.livsci.2022.105145. S2CID 254914487.
  121. ^ Xu, Yongjie; Lai, Xiaodan; Li, Zhipeng; Zhang, Xiquan; Luo, Qingbin (November 1, 2018). "Effect of chronic heat stress on some physiological and immunological parameters in different breed of broilers". Poultry Science. 97 (11): 4073–4082. doi:10.3382/ps/pey256. PMC 6162357. PMID 29931080.
  122. ^ Orhan, Cemal; Tuzcu, Mehmet; Deeh, Patrick Brice Defo; Sahin, Nurhan; Komorowski, James R.; Sahin, Kazim (August 21, 2018). "Organic Chromium Form Alleviates the Detrimental Effects of Heat Stress on Nutrient Digestibility and Nutrient Transporters in Laying Hens". Biological Trace Element Research. 189 (2): 529–537. doi:10.1007/s12011-018-1485-9. PMID 30132119. S2CID 255452740.
  123. ^ Sahin, N; Hayirli, A; Orhan, C; Tuzcu, M; Akdemir, F; Komorowski, J R; Sahin, K (December 11, 2019). "Effects of the supplemental chromium form on performance and oxidative stress in broilers exposed to heat stress". Poultry Science. 96 (12): 4317–4324. doi:10.3382/ps/pex249. PMID 29053811. S2CID 10630678.
  124. ^ Untea, Arabela Elena; Varzaru, Iulia; Turcu, Raluca Paula; Panaite, Tatiana Dumitra; Saracila, Mihaela (October 13, 2021). "The use of dietary chromium associated with vitamins and minerals (synthetic and natural source) to improve some quality aspects of broiler thigh meat reared under heat stress condition". Italian Journal of Animal Science. 20 (1): 1491–1499. doi:10.1080/1828051X.2021.1978335. S2CID 244583811.
  125. ^ Ding, Kang-Ning; Lu, Meng-Han; Guo, Yan-Na; Liang, Shao-Shan; Mou, Rui-Wei; He, Yong-Ming He; Tang, Lu-Ping (December 14, 2022). "Resveratrol relieves chronic heat stress-induced liver oxidative damage in broilers by activating the Nrf2-Keap1 signaling pathway". Ecotoxicology and Environmental Safety. 249: 114411. doi:10.1016/j.ecoenv.2022.114411. PMID 36525949. S2CID 254723325.
  126. ^ Sahin, K; Sahin, N; Kucuk, O; Hayirli, A; Prasad, A. S. (October 1, 2009). "Role of dietary zinc in heat-stressed poultry: A review". Poultry Science. 88 (10): 2176–2183. doi:10.3382/ps.2008-00560. PMID 19762873.
  127. ^ El-Tarabany, Mahmoud S. (August 27, 2016). "Effect of thermal stress on fertility and egg quality of Japanese quail". Journal of Thermal Biology. 61: 38–43. doi:10.1016/j.jtherbio.2016.08.004. PMID 27712658.
  128. ^ Bilal, Rana Muhammad; Hassan, Faiz-ul; Farag, Mayada R.; Nasir, Taquir Ali; Ragni, Marco; Ahsan, Umair; Güven, Gülşen (April 20, 2021). "Thermal stress and high stocking densities in poultry farms: Potential effects and mitigation strategies". Journal of Thermal Biology. 99: 102944. doi:10.1016/j.jtherbio.2021.102944. PMID 34420608. S2CID 233555119.
  129. ^ Kucuk, O. (January 10, 2008). "Zinc in a Combination with Magnesium Helps Reducing Negative Effects of Heat Stress in Quails". Biological Trace Element Research. 123 (1–3): 144–153. doi:10.1007/s12011-007-8083-6. PMID 18188513. S2CID 24775551.
  130. ^ de Carvalho Curi, T. M. R.; de Alencar Nääs, I.; da Silva Lima, N. D.; Martinez, A. A. G. (January 24, 2022). "Climate change impact on Brazilian broiler production cost: a simulation study". International Journal of Environmental Science and Technology. 19 (11): 10589–10598. doi:10.1007/s13762-021-03893-z. S2CID 246211499.

External links

  •   Media related to Chickens at Wikimedia Commons
  •   The dictionary definition of cockerel at Wiktionary
  •   Data related to Gallus gallus domesticus at Wikispecies

November 29, 2023
chicken, culinary, chickens, food, other, uses, disambiguation, chooks, disambiguation, rooster, roosters, redirect, here, other, uses, rooster, disambiguation, cockerel, redirects, here, fabergé, cockerel, fabergé, chicken, gallus, domesticus, domesticated, s. For the culinary use of chickens see Chicken as food For other uses see Chicken disambiguation and Chooks disambiguation Rooster and Roosters redirect here For other uses see Rooster disambiguation Cockerel redirects here For the Faberge egg see Cockerel Faberge egg The chicken Gallus domesticus is a domesticated species that arose from the red junglefowl originally from Southeast Asia They have also partially hybridized with other wild species of junglefowl the grey junglefowl Ceylon junglefowl and green junglefowl 1 Rooster and cock are terms for adult male birds and a younger male may be called a cockerel A male that has been castrated is a capon An adult female bird is called a hen and a sexually immature female is called a pullet Humans keep chickens primarily as a source of food consuming both their meat and eggs or as pets Traditionally they were also bred for cockfighting which is still practiced in some places Chickens domesticated for meat are broilers and for eggs they are layers ChickenA rooster left and hen right perching on a roostConservation statusDomesticatedScientific classificationDomain EukaryotaKingdom AnimaliaPhylum ChordataClass AvesOrder GalliformesFamily PhasianidaeGenus GallusSpecies G domesticusBinomial nameGallus domesticus Linnaeus 1758 Chicken distributionChickens are one of the most common and widespread domestic animals with a total population of 23 7 billion as of 2018 update 2 up from more than 19 billion in 2011 There are more chickens in the world than any other bird There are numerous cultural references to chickens in myth folklore and religion as well as in language and literature Genetic studies have pointed to multiple maternal origin theories within South Asia Southeast Asia and East Asia 3 but the clade found in the Americas Europe the Middle East and Africa originated from the Indian subcontinent From ancient India the chicken spread to the Eastern Mediterranean They appear in ancient Egypt in the mid 15th century BC with the bird that gives birth every day having come from the land between Syria and Shinar Babylonia according to the annals of Thutmose III 4 5 6 They are known in ancient Greece from the 5th century BC 7 8 Contents 1 Terminology 2 Etymology 3 Biology and habitat 3 1 Behavior 3 1 1 Social behaviour 3 1 2 Vocalizations 3 1 2 1 Crowing 3 1 3 Courtship 3 1 4 Nesting and laying behaviour 3 1 5 Broodiness 3 1 6 Hatching and early life 3 2 Reproduction 3 3 Embryology 3 4 Genetics and genomics 3 5 Physiology 4 Origin and dispersal 4 1 Origin 4 2 Domestication 4 3 Dispersal 4 3 1 South America 5 Use by humans 5 1 Farming 5 1 1 Reared for meat 5 1 2 Reared for eggs 5 2 As pets 5 3 Cockfighting 5 4 Artificial incubation 6 Diseases and ailments 6 1 Impacts of climate change 7 Gallery 8 Notes 9 References 10 External linksTerminology nbsp In most breeds the adult rooster can be distinguished from the hen by his larger comb nbsp Comb of a hen An adult male is a called a cock or in the United States a rooster and an adult female is called a hen 9 10 Other terms are Biddy a newly hatched chicken 11 12 Capon a castrated or neutered male chicken a Chick a young chicken 13 Chook tʃ ʊ k a chicken Australia New Zealand informal 14 Cockerel a young male chicken less than a year old 15 Dunghill fowl a chicken with mixed parentage from different domestic varieties 16 Pullet a young female chicken less than a year old 17 In the poultry industry a pullet is a sexually immature chicken less than 22 weeks of age 18 Yardbird a chicken southern United States dialectal 19 Chicken may also mean a chick see for example Hen and Chicken Islands 20 In fact chicken was originally a term only for an immature or at least young bird when In older sources and still often in trade and scientific contexts chicken as a species are typically referred to as common fowl or domestic fowl 21 In Australian vernacular English the word chook provides the generic term for the species e g a cooked chook or she keeps chooks which enables chicken to commonly retain its original sense of a young or recently hatched bird Chick is then rarely used to mean chicken but is mainly used in Merriam Webster s Sense 1b viz the young of any bird EtymologyAccording to Merriam Webster the term rooster i e a roosting bird originated in the mid or late 18th century as a euphemism to avoid the sexual connotation of the original English cock 22 23 24 and is widely used throughout North America Roosting is the action of perching aloft to sleep at night 25 Biology and habitatChickens are omnivores 26 In the wild they often scratch at the soil to search for seeds insects and even animals as large as lizards small snakes 27 or sometimes young mice 28 The average chicken may live for 5 10 years depending on the breed 29 The world s oldest known chicken lived for 16 years according to Guinness World Records 30 Roosters can usually be differentiated from hens by their striking plumage of long flowing tails and shiny pointed feathers on their necks hackles and backs saddle which are typically of brighter bolder colours than those of females of the same breed However in some breeds such as the Sebright chicken the rooster has only slightly pointed neck feathers the same colour as the hen s Identification can be made by looking at the comb or eventually by the development of spurs on the male s legs in a few breeds and in certain hybrids the male and female chicks may be differentiated by colour Adult chickens have a fleshy crest on their heads called a comb or cockscomb and hanging flaps of skin on either side under their beaks called wattles Collectively these and other fleshy protuberances on the head and throat are called caruncles Both the adult male and female have wattles and combs but in most breeds these are more prominent in males A muff or beard is a mutation found in several chicken breeds that causes extra feathering under the chicken s face giving the appearance of a beard 31 Domestic chickens are not capable of long distance flight although lighter chickens are generally capable of flying for short distances such as over fences or into trees where they would naturally roost Chickens may occasionally fly briefly to explore their surroundings but generally do so only to flee perceived danger Behavior Social behaviour See also Empathy in chickens nbsp Hen with chicksChickens are gregarious birds and live together in flocks They have a communal approach to the incubation of eggs and raising of young Individual chickens in a flock will dominate others establishing a pecking order with dominant individuals having priority for food access and nesting locations Removing hens or roosters from a flock causes a temporary disruption to this social order until a new pecking order is established Adding hens especially younger birds to an existing flock can lead to fighting and injury citation needed Chickens may occasionally gang up on a weak or inexperienced predator At least one credible report exists of a young fox killed by hens 32 33 34 If a chicken is threatened by predators stress or is sick it may puff up its feathers 35 Vocalizations When a rooster finds food he may call other chickens to eat first He does this by clucking in a high pitch as well as picking up and dropping the food This behaviour may also be observed in mother hens to call their chicks and encourage them to eat A rooster s crowing is a loud and sometimes shrill call and sends a territorial signal to other roosters 36 However roosters may also crow in response to sudden disturbances within their surroundings Hens cluck loudly after laying an egg and also to call their chicks Chickens also give different warning calls when they sense a predator approaching from the air or on the ground 37 Crowing Cockadoodledoo and Cocka doodle doo redirect here For the nursery rhyme see Cock a doodle doo nbsp Bergische Kraher crowing source source The long crowing of a Bergische Kraher source source source Normal length crowing with audio Long crowing chickens have a longer crow Roosters almost always start crowing before four months of age Although it is possible for a hen to crow as well crowing together with hackles development is one of the clearest signs of being a rooster citation needed Rooster crowing contests are a traditional sport in several countries such as Germany the Netherlands Belgium 38 the United States Indonesia and Japan The oldest contests are held with longcrowers Depending on the breed either the duration of the crowing or the times the rooster crows within a certain time is measured Courtship To initiate courting some roosters may dance in a circle around or near a hen a circle dance often lowering the wing which is closest to the hen 39 The dance triggers a response in the hen 39 and when she responds to his call the rooster may mount the hen and proceed with the mating More specifically mating typically involves the following sequence Male approaching the hen Male pre copulatory waltzing Male waltzing Female crouching receptive posture or stepping aside or running away if unwilling to copulate Male mounting Male treading with both feet on hen s back Male tail bending following successful copulation 40 Nesting and laying behaviour Hens will often try to lay in nests that already contain eggs and have been known to move eggs from neighbouring nests into their own The result of this behaviour is that a flock will use only a few preferred locations rather than having a different nest for every bird Hens will often express a preference to lay in the same location Two or more hens may try to share the same nest at the same time If the nest is small or one of the hens is particularly determined this may result in chickens trying to lay on top of each other There is evidence that individual hens prefer to be either solitary or gregarious nesters 41 Broodiness This section needs additional citations for verification Please help improve this article by adding citations to reliable sources in this section Unsourced material may be challenged and removed June 2021 Learn how and when to remove this template message nbsp Chicken eggs vary in colour depending on the breed and sometimes the hen typically ranging from bright white to shades of brown and even blue green light pinkish and purple Under natural conditions most birds lay only until a clutch is complete and they will then incubate all the eggs Hens are then said to go broody The broody hen will stop laying and instead will focus on the incubation of the eggs a full clutch is usually about 12 eggs She will sit or set on the nest fluffing up or pecking in defense if disturbed or removed The hen will rarely leave the nest to eat drink or dust bathe 35 While brooding the hen maintains the nest at a constant temperature and humidity as well as turning the eggs regularly during the first part of the incubation To stimulate broodiness owners may place several artificial eggs in the nest To discourage it they may place the hen in an elevated cage with an open wire floor Breeds artificially developed for egg production rarely go broody and those that do often stop part way through the incubation However other breeds such as the Cochin Cornish and Silkie do regularly go broody and make excellent mothers not only for chicken eggs but also for those of other species even those with much smaller or larger eggs and different incubation periods such as quail pheasants ducks turkeys or geese Hatching and early life nbsp Two Lavender Orpington chicks nbsp A group of chicksFertile chicken eggs hatch at the end of the incubation period about 21 days 39 Development of the chick starts only when incubation begins so all chicks hatch within a day or two of each other despite perhaps being laid over a period of two weeks or so Before hatching the hen can hear the chicks peeping inside the eggs and will gently cluck to stimulate them to break out of their shells The chick begins by pipping pecking a breathing hole with its egg tooth towards the blunt end of the egg usually on the upper side The chick then rests for some hours absorbing the remaining egg yolk and withdrawing the blood supply from the membrane beneath the shell used earlier for breathing through the shell The chick then enlarges the hole gradually turning round as it goes and eventually severing the blunt end of the shell completely to make a lid The chick crawls out of the remaining shell and the wet down dries out in the warmth of the nest Hens usually remain on the nest for about two days after the first chick hatches and during this time the newly hatched chicks feed by absorbing the internal yolk sac Some breeds sometimes start eating cracked eggs which can become habitual 42 Hens fiercely guard their chicks and brood them when necessary to keep them warm at first often returning to the nest at night She leads them to food and water and will call them toward edible items but seldom feeds them directly She continues to care for them until they are several weeks old Reproduction Sperm transfer occurs by cloacal contact between the male and female in a maneuver known as the cloacal kiss 43 As with birds in general reproduction is controlled by a neuroendocrine system the Gonadotropin Releasing Hormone I neurons in the hypothalamus Locally to the reproductive system reproductive hormones such as estrogen progesterone gonadotropins luteinizing hormone and follicle stimulating hormone initiate and maintain sexual maturation changes Over time there is reproductive decline thought to be due to GnRH I N decline Because there is significant inter individual variability in egg producing duration it is believed to be possible to breed for further extended useful lifetime in egg layers 44 Embryology source source source Video Earliest gestation stages and blood circulation of a chicken embryoChicken embryos have long been used as model organisms to study developing embryos Large numbers of embryos can be provided by commercial chicken farmers who sell fertilized eggs which can be easily opened and used to observe the developing embryo Equally important embryologists can carry out experiments on such embryos close the egg again and study the effect later on For instance many important discoveries in the area of limb development have been made using chicken embryos such as the discovery of the apical ectodermal ridge and the zone of polarizing activity by John W Saunders 45 In 2006 scientists researching the ancestry of birds turned on a chicken recessive gene talpid2 and found that the embryo jaws initiated formation of teeth like those found in ancient bird fossils John Fallon the overseer of the project stated that chickens have retained the ability to make teeth under certain conditions 46 Genetics and genomics nbsp Mottle geneGiven its eminent role in farming meat production but also research the house chicken was the first bird genome to be sequenced 47 At 1 21 Gb the chicken genome is similarly sized compared to other birds but smaller than nearly all mammals such as the human genome of 3 2 Gb 48 The final gene set contained 26 640 genes including noncoding genes and pseudogenes with a total of 19 119 protein coding genes in annotation release 103 2017 a similar number of protein coding genes as in the human genome 49 Physiology Populations of chickens from high altitude regions like Tibet have special physiological adaptations that result in a higher hatching rate in low oxygen environments When eggs are placed in a hypoxic environment chicken embryos from these populations express much more hemoglobin than embryos from other chicken populations This hemoglobin also has a greater affinity for oxygen allowing hemoglobin to bind to oxygen more readily 50 Pinopsins were originally discovered in the chicken pineal gland 51 Although all avians appear to have lost TLR9 artificial immunity against bacterial pathogens has been induced in neonatal chicks by Taghavi et al 2008 using tailored oligodeoxynucleotides 52 Origin and dispersalOrigin Galliformes the order of bird that chickens belong to is directly linked to the survival of birds when all other dinosaurs went extinct Water or ground dwelling fowl similar to modern partridges survived the Cretaceous Paleogene extinction event that killed all tree dwelling birds and dinosaurs 53 Some of these evolved into the modern galliformes of which domesticated chickens are a main model They are descended primarily from the red junglefowl Gallus gallus and are scientifically classified as the same species 54 As such domesticated chickens can and do freely interbreed with populations of red junglefowl 54 Subsequent hybridization of the domestic chicken with grey junglefowl Sri Lankan junglefowl and green junglefowl occurred 55 a gene for yellow skin for instance was incorporated into domestic birds through hybridization with the grey junglefowl G sonneratii 56 In a study published in 2020 it was found that chickens shared between 71 79 of their genome with red junglefowl with the period of domestication dated to 8 000 years ago 55 Domestication According to one early study a single domestication event of the red junglefowl in present day Thailand gave rise to the modern chicken with minor transitions separating the modern breeds 57 The red junglefowl is well adapted to take advantage of the vast quantities of seed produced during the end of the multi decade bamboo seeding cycle to boost its own reproduction 58 In domesticating the chicken humans took advantage of this predisposition for prolific reproduction of the red junglefowl when exposed to large amounts of food 59 Exactly when and where the chicken was domesticated remains a controversial issue Genomic studies estimate that the chicken was domesticated 8 000 years ago 55 in Southeast Asia and spread to China and India 2 000 to 3 000 years later Archaeological evidence supports domestic chickens in Southeast Asia well before 6000 BC China by 6000 BC and India by 2000 BC 55 60 61 A landmark 2020 Nature study that fully sequenced 863 chickens across the world suggests that all domestic chickens originate from a single domestication event of red junglefowl whose present day distribution is predominantly in southwestern China northern Thailand and Myanmar These domesticated chickens spread across Southeast and South Asia where they interbred with local wild species of junglefowl forming genetically and geographically distinct groups Analysis of the most popular commercial breed shows that the White Leghorn breed possesses a mosaic of divergent ancestries inherited from subspecies of red junglefowl 62 63 64 Dispersal nbsp Map showing the prehistoric introduction of domesticated chickens into Oceania from the Philippines via the Neolithic Austronesian expansion starting at c 4000 BP inferred from genetic markers on ancient and modern chicken DNA Thomson et al 2014 65 A word for the domestic chicken manuk is part of the reconstructed Proto Austronesian language indicating they were domesticated by the Austronesian peoples since ancient times Chickens together with dogs and pigs were carried throughout the entire range of the prehistoric Austronesian maritime migrations to Island Southeast Asia Micronesia Island Melanesia Polynesia and Madagascar starting from at least 3000 BC from Taiwan 65 66 67 68 These chickens might have been introduced during pre Columbian times to South America via Polynesian seafarers but evidence for this is still putative 69 Middle Eastern chicken remains go back to a little earlier than 2000 BC in Syria They reached Egypt for purposes of cockfighting about 1400 BC and became widely bred in Egypt around 300 BC 70 Phoenicians spread chickens along the Mediterranean coasts as far as Iberia During the Hellenistic period 4th 2nd centuries BC in the southern Levant chickens began to be widely domesticated for food 71 This change occurred at least 100 years before domestication of chickens spread to Europe The first pictures of chickens in Europe are found on Corinthian pottery of the 7th century BC 72 73 Chickens reached Europe c 100 BC 74 Breeding increased under the Roman Empire and reduced by the Middle Ages 70 Genetic sequencing of chicken bones from archaeological sites in Europe revealed that in the High Middle Ages chickens became less aggressive and began to lay eggs earlier in the breeding season 75 Three possible routes of introduction into Africa around the early first millennium AD could have been through the Egyptian Nile Valley the East Africa Roman Greek or Indian trade or from Carthage and the Berbers across the Sahara The earliest known remains are from Mali Nubia East Coast and South Africa and date back to the middle of the first millennium AD 70 Domestic chicken in the Americas before Western contact is still an ongoing discussion but blue egged chickens found only in the Americas and Asia suggest an Asian origin for early American chickens 70 A lack of data from Thailand Russia the Indian subcontinent Southeast Asia and Sub Saharan Africa makes it difficult to lay out a clear map of the spread of chickens in these areas better description and genetic analysis of local breeds threatened by extinction may also help with research into this area 70 South America An unusual variety of chicken that has its origins in South America is the Araucana bred in southern Chile by the Mapuche people Araucanas lay blue green eggs Additionally some Araucanas are tailless and some have tufts of feathers around their ears It has long been suggested that they pre date the arrival of European chickens brought by the Spanish and are evidence of pre Columbian trans Pacific contacts between Asian or Pacific Oceanic peoples particularly the Polynesians and South America In 2007 an international team of researchers reported the results of their analysis of chicken bones found on the Arauco Peninsula in south central Chile Radiocarbon dating suggested that the chickens were pre Columbian and DNA analysis showed that they were related to prehistoric populations of chickens in Polynesia 76 These results appeared to confirm that the chickens came from Polynesia and that there were transpacific contacts between Polynesia and South America before Columbus arrival in the Americas 77 78 However a later report looking at the same specimens concluded A published apparently pre Columbian Chilean specimen and six pre European Polynesian specimens also cluster with the same European Indian subcontinental Southeast Asian sequences providing no support for a Polynesian introduction of chickens to South America In contrast sequences from two archaeological sites on Easter Island group with an uncommon haplogroup from Indonesia Japan and China and may represent a genetic signature of an early Polynesian dispersal Modeling of the potential marine carbon contribution to the Chilean archaeological specimen casts further doubt on claims for pre Columbian chickens and definitive proof will require further analyses of ancient DNA sequences and radiocarbon and stable isotope data from archaeological excavations within both Chile and Polynesia 79 The debate for and against a Polynesian origin for South American chickens continued with this 2014 paper and subsequent responses in PNAS 80 Use by humansFarming Main articles Poultry farming and Chicken as food nbsp A former battery hen five days after release Note the pale comb the comb may be an indicator of health or vigor 81 More than 50 billion chickens are reared annually as a source of meat and eggs 82 In the United States alone more than 8 billion chickens are slaughtered each year for meat 83 and more than 300 million chickens are reared for egg production 84 The vast majority of poultry is raised in factory farms According to the Worldwatch Institute 74 of the world s poultry meat and 68 of eggs are produced this way 85 An alternative to intensive poultry farming is free range farming Friction between these two main methods has led to long term issues of ethical consumerism Opponents of intensive farming argue that it harms the environment creates human health risks and is inhumane 86 Advocates of intensive farming say that their highly efficient systems save land and food resources owing to increased productivity and that the animals are looked after in state of the art environmentally controlled facilities 87 Reared for meat nbsp A commercial chicken house with open sides raising broiler pullets for meatChickens farmed for meat are called broilers Chickens will naturally live for six or more years but broiler breeds typically take less than six weeks to reach slaughter size 88 A free range or organic broiler will usually be slaughtered at about 14 weeks of age Reared for eggs Main article Egg as food Chickens farmed primarily for eggs are called layer hens In total the UK alone consumes more than 34 million eggs per day 89 Some hen breeds can produce over 300 eggs per year with the highest authenticated rate of egg laying being 371 eggs in 364 days 90 After 12 months of laying the commercial hen s egg laying ability starts to decline to the point where the flock is commercially unviable Hens particularly from battery cage systems are sometimes infirm or have lost a significant amount of their feathers and their life expectancy has been reduced from around seven years to less than two years 91 In the UK and Europe laying hens are then slaughtered and used in processed foods or sold as soup hens 91 In some other countries flocks are sometimes force moulted rather than being slaughtered to re invigorate egg laying This involves complete withdrawal of food and sometimes water for 7 14 days 92 or sufficiently long to cause a body weight loss of 25 to 35 93 or up to 28 days under experimental conditions 94 This stimulates the hen to lose her feathers but also re invigorates egg production Some flocks may be force moulted several times In 2003 more than 75 of all flocks were moulted in the US 95 As pets nbsp Woman with roosterKeeping chickens as pets became increasingly popular in the 2000s 96 among urban and suburban residents 97 Many people obtain chickens for their egg production but often name them and treat them as any other pet like cats or dogs Chickens provide companionship and have individual personalities While many do not cuddle much they will eat from one s hand jump onto one s lap respond to and follow their handlers as well as show affection 98 99 Chickens are social inquisitive intelligent 100 birds and many find their behaviour entertaining 101 Certain breeds such as silkies and many bantam varieties are generally docile and are often recommended as good pets around children with disabilities 102 Many people feed chickens in part with kitchen food scraps nbsp Backyard heritage chickens eating kitchen food scraps 103 Cockfighting nbsp Two cocks fightingA cockfight is a contest held in a ring called a cockpit between two cocks known as gamecocks This term denoting a cock kept for game sport pastime or entertainment appears in 1646 104 after cock of the game used by George Wilson in the earliest known book on the secular sport The Commendation of Cocks and Cock Fighting of 1607 Gamecocks are not typical farm chickens The cocks are specially bred and trained for increased stamina and strength The comb and wattle are removed from a young gamecock because if left intact they would be a disadvantage during a match This process is called dubbing Sometimes the cocks are given drugs to increase their stamina or thicken their blood which increases their chances of winning Cockfighting is considered a traditional sporting event by some but an example of animal cruelty by others and is therefore outlawed in most countries 105 Usually wagers are made on the outcome of the match with the survivor or last bird standing declared winner Cocks possess congenital aggression toward other cocks to contest for females Studies suggest that cockfights have existed even up to the Indus Valley civilisation as a pastime 106 Today it is commonly associated with religious worship pastime and gambling in Asian and some South American countries While not all fights are to the death most use metal spurs as a weapon attached above or below the chicken s own spur which typically results in death in one or both cocks If chickens are in practice owners place gloves on the spurs to prevent injuries Artificial incubation Incubation can occur artificially in machines that provide the correct controlled environment for the developing chick 107 108 The average incubation period for chickens is 21 days but the duration depends on the temperature and humidity in the incubator Temperature regulation is the most critical factor for a successful hatch Variations of more than 1 C 1 8 F from the optimum temperature of 37 5 C 99 5 F will reduce hatch rates Humidity is also important because the rate at which eggs lose water by evaporation depends on the ambient relative humidity Evaporation can be assessed by candling to view the size of the air sac or by measuring weight loss Relative humidity should be increased to around 70 in the last three days of incubation to keep the membrane around the hatching chick from drying out after the chick cracks the shell Lower humidity is usual in the first 18 days to ensure adequate evaporation The position of the eggs in the incubator can also influence hatch rates For best results eggs should be placed with the pointed ends down and turned regularly at least three times per day until one to three days before hatching If the eggs are not turned the embryo inside may stick to the shell and may hatch with physical defects Adequate ventilation is necessary to provide the embryo with oxygen Older eggs require increased ventilation Many commercial incubators are industrial sized with shelves holding tens of thousands of eggs at a time with rotation of the eggs a fully automated process Home incubators are boxes holding from 6 to 75 eggs Diseases and ailmentsSee also Poultry disease Chickens are susceptible to several parasites including lice mites ticks fleas and intestinal worms as well as other diseases Despite the name they are not affected by chickenpox which is generally restricted to humans 109 Chickens can carry and transmit salmonella in their dander and feces In the United States the Centers for Disease Control and Prevention advise against bringing them indoors or letting small children handle them 110 111 Some of the diseases that can affect chickens are shown below Name Common name CauseAspergillosis Aspergillus fungiAvian influenza bird flu virusHistomoniasis blackhead disease Histomonas meleagridisBotulism paralysis Clostridium botulinum toxinCage layer fatigue mineral deficiency lack of physical exerciseCampylobacteriosis tissue injury in the gutCoccidiosis CoccidiaColds virusCrop bound 112 improper feedingDermanyssus gallinae red mite parasiteEgg binding oversized eggErysipelas Streptococcus bacteriaFatty liver hemorrhagic syndrome high energy foodFowl cholera Pasteurella multocidaFowlpox Fowlpox virusFowl typhoid bacteriaAvian infectious laryngotracheitis LT Gallid alphaherpesvirus 1Gapeworm Syngamus trachea wormsInfectious bronchitis 113 Infectious bronchitis virusInfectious bursal disease Gumboro infectious bursal disease virusInfectious coryza in chickens Avibacterium paragallinarumLymphoid leukosis Avian sarcoma leukosis virusMarek s disease Gallid alphaherpesvirus 2Moniliasis yeast infectionor thrush Candida fungiMycoplasma bacteriaNewcastle disease Avian avulavirus 1Necrotic enteritis 114 bacteriaOmphalitis Mushy chick disease 115 bacteriaPeritonitis 116 infection in abdomen from egg yolkPsittacosis Chlamydia psittaciPullorum Salmonella bacteriaScaly leg Knemidokoptes mutansSquamous cell carcinoma cancerTibial dyschondroplasia speed growingToxoplasmosis Toxoplasma gondiiTrichomoniasis roup Trichomonas gallinaeUlcerative enteritis 117 bacteriaUlcerative pododermatitis bumblefoot bacteriaImpacts of climate change This section is an excerpt from Effects of climate change on livestock Poultry edit nbsp Photo of an egg farm in New England taken around 2009 It is believed that the thermal comfort zone for poultry is in the 18 25 C 64 77 F range Some papers describe 26 35 C 79 95 F as the critical zone for heat stress but others report that due to acclimatization birds in the tropical countries do not begin to experience heat stress until 32 C 90 F There is wider agreement that temperatures greater than 35 C 95 F and 47 C 117 F form upper critical and lethal zones respectively 118 Average daily temperatures of around 33 C 91 F are known to interfere with feeding in both broilers and egg hens as well as lower their immune response with outcomes such as reduced weight gain egg production or greater incidence of salmonella infections footpad dermatitis or meningitis Persistent heat stress leads to oxidative stress in tissues and harvested white meat ends up with a lower proportion of essential compounds like vitamin E lutein and zeaxanthin yet an increase in glucose and cholesterol Multiple studies show that dietary supplementation with chromium can help to relieve these issues due to its antioxidative properties particularly in combination with zinc or herbs like wood sorrel 119 120 121 122 123 124 Resveratrol is another popular antioxidant administered to poultry for these reasons 125 Though the effect of supplementation is limited it is much cheaper than interventions to improve cooling or simply stock fewer birds and so remains popular 126 While the majority of literature on poultry heat stress and dietary supplementation focuses on chickens similar findings were seen in Japanese quails which eat less and gain less weight suffer reduced fertility and hatch eggs of worse quality under heat stress and also seem to benefit from mineral supplementation 127 128 129 Around 2003 it was estimated that the poultry industry in the United States already lost up to 165 million annually due to heat stress at the time 118 One paper estimated that if global warming reaches 2 5 C 4 5 F then the cost of rearing broilers in Brazil increases by 35 8 at the least modernized farms and by 42 3 at farms with the medium level of technology used in livestock housing while they increase the least at farms with the most advanced cooling technologies On the contrary if the warming is kept to 1 5 C 2 7 F costs at moderately modernized farms increase the least by 12 5 followed by the most modernized farms with a 19 9 increase and the least technological farms seeing the greatest increase 130 Gallery nbsp Brown Leghorn nbsp Joseph Crawhall III Spanish Cock and Snail nbsp Rooster and hen Vietnamese Đong Hồ painting nbsp Vinh hoa Đong Hồ painting Vietnam nbsp Wikimedia Commons has media related to Category Chickens nbsp Wikimedia Commons has media related to Category Gallus gallus Notes The surgical and chemical castration of chickens is now illegal in some parts of the world References Lawal Raman Akinyanju Martin Simon H Vanmechelen Koen Vereijken Addie Silva Pradeepa Al Atiyat Raed Mahmoud Aljumaah Riyadh Salah Mwacharo Joram M Wu Dong Dong Zhang Ya Ping Hocking Paul M Smith Jacqueline Wragg David Hanotte Olivier February 12 2020 The wild species genome ancestry of domestic chickens BMC Biology BioMed Central 18 1 13 doi 10 1186 s12915 020 0738 1 ISSN 1741 7007 PMC 7014787 PMID 32050971 S2CID 211081254 Tiley George P Poelstra Jelmer W dos Reis Mario Yang Ziheng Yoder Anne D 2020 Molecular Clocks without Rocks New Solutions for Old Problems Trends in Genetics Cell Press 36 11 845 856 doi 10 1016 j tig 2020 06 002 ISSN 0168 9525 PMID 32709458 S2CID 220747034 Archived from the original on June 11 2022 Retrieved April 11 2022 Tregaskes Clive A Kaufman Jim 2021 Chickens as a simple system for scientific discovery The example of the MHC Molecular Immunology Elsevier 135 12 20 doi 10 1016 j molimm 2021 03 019 ISSN 0161 5890 PMC 7611830 PMID 33845329 S2CID 233223219 EuroPMC manus 136199 Lawal R A Hanotte O May 31 2021 Domestic chicken diversity Origin distribution and adaptation Animal Genetics International Foundation for Animal Genetics Wiley 52 4 385 394 doi 10 1111 age 13091 ISSN 0268 9146 PMID 34060099 S2CID 235268576 Siegel Paul B Honaker Christa F Scanes Colin G 2022 Domestication of poultry Sturkie s Avian Physiology Elsevier pp 109 120 doi 10 1016 b978 0 12 819770 7 00026 8 ISBN 978 0 12 819770 7 S2CID 244084328 Eda Masaki May 1 2021 Origin of the domestic chicken from modern biological and zooarchaeological approaches Animal Frontiers American Society of Animal Science OUP 11 3 52 61 doi 10 1093 af vfab016 ISSN 2160 6056 PMC 8214436 PMID 34158989 S2CID 235593797 van Grouw Hein Dekkers Wim September 21 2020 Temminck s Gallus giganteus a gigantic obstacle to Darwin s theory of domesticated fowl origin Bulletin of the British Ornithologists Club British Ornithologists Club 140 3 doi 10 25226 bboc v140i3 2020 a5 ISSN 0007 1595 S2CID 221823963 Number of chickens worldwide from 1990 to 2018 Statista Archived from the original on November 27 2020 Retrieved February 23 2020 Xiang Hai Gao Jianqiang Yu Baoquan Zhou Hui Cai Dawei Zhang Youwen Chen Xiaoyong Wang Xi Hofreiter Michael Zhao Xingbo December 9 2014 Early Holocene chicken domestication in northern China Proceedings of the National Academy of Sciences 111 49 17564 17569 Bibcode 2014PNAS 11117564X doi 10 1073 pnas 1411882111 PMC 4267363 PMID 25422439 Carter Howard April 1923 An Ostracon Depicting a Red Jungle Fowl The Earliest Known Drawing of the Domestic Cock The Journal of Egyptian Archaeology 9 1 2 1 4 doi 10 2307 3853489 JSTOR 3853489 Pritchard Earl H The Asiatic Campaigns of Thutmose III Ancient Near East Texts related to the Old Testament p 240 Roehrig Catharine H Dreyfus Renee Keller Cathleen A 2005 Hatshepsut From Queen to Pharaoh New York Metropolitan Museum of Art p 268 ISBN 978 1 58839 173 5 Retrieved November 26 2015 Toussaint Samat Maguelonne 2009 11 The History of Poultry The History of Food Translated by Bell Anthea revised ed Blackwell p 306 ISBN 978 0631177418 Perry Gal Lee Erlich Adi Gilboa Ayelet Bar Oz Guy August 11 2015 Earliest economic exploitation of chicken outside East Asia Evidence from the Hellenistic Southern Levant Proceedings of the National Academy of Sciences 112 32 9849 9854 Bibcode 2015PNAS 112 9849P doi 10 1073 pnas 1504236112 PMC 4538678 PMID 26195775 Cock Cambridge Dictionary Archived from the original on September 7 2015 Retrieved March 4 2021 Hen Cambridge Dictionary Archived from the original on September 7 2015 Retrieved March 4 2021 Definition of biddy Dictionary com www dictionary com Archived from the original on May 7 2021 Retrieved May 7 2021 Biddy definition and meaning Collins English Dictionary www collinsdictionary com Archived from the original on May 7 2021 Retrieved May 7 2021 Chick Cambridge Dictionary Archived from the original on September 7 2015 Chook Cambridge Dictionary Archived from the original on September 7 2015 Retrieved March 4 2021 Cockerel Dictionary reference com Archived from the original on March 7 2016 Retrieved August 29 2010 Richardson H D 1847 Domestic fowl their natural history breeding rearing and general management Archived from the original on June 11 2022 Retrieved March 30 2022 Pullet Dictionary reference com Archived from the original on November 9 2010 Retrieved August 29 2010 Overview of the Poultry Industry PDF Overview of the Poultry Industry Missouri Department of Elementary and Secondary Education p 8 Archived PDF from the original on October 23 2020 Berhardt Clyde E B 1986 I Remember Eighty Years of Black Entertainment Big Bands Philadelphia University of Pennsylvania Press p 153 ISBN 978 0 8122 8018 0 OCLC 12805260 Chicken Merriam Webster Dictionary Archived from the original on August 21 2008 Retrieved March 4 2021 Stevens Lewis Genetics and evolution of the domestic fowl p 1 and throughout 1991 Cambridge University Press google books Definition of ROOSTER www merriam webster com Archived from the original on April 22 2021 Retrieved March 6 2021 Hugh Rawson Archived July 1 2017 at the Wayback Machine Why Do We Say Rooster American Heritage August September 2006 Online Etymology Dictionary Archived November 11 2020 at the Wayback Machine Entry for rooster n May 2019 Definition of ROOST Collins English Dictionary Archived from the original on May 1 2021 Retrieved October 16 2021 Info on Chicken Care Ideas 4 pets co uk 2003 Archived from the original on June 25 2015 Retrieved August 13 2008 D Lines July 27 2013 Chicken Kills Rattlesnake YouTube Archived from the original on December 11 2021 Retrieved March 13 2019 Gerard P Worrell AKA Farmer Jerry Frequently asked questions about chickens amp eggs Gworrell freeyellow com Archived from the original on September 16 2008 Retrieved August 13 2008 The Poultry Guide A to Z and FAQs Ruleworks co uk Archived from the original on November 28 2010 Retrieved August 29 2010 Smith Jamon August 6 2006 World s oldest chicken starred in magic shows was on Tonight Show Tuscaloosa News Alabama USA Archived from the original on February 20 2019 Retrieved May 18 2020 Ying Guo Xiaorong Gu Zheya Sheng Yanqiang Wang Chenglong Luo Ranran Liu Hao Qu Dingming Shu Jie Wen Richard P M A Crooijmans Orjan Carlborg Yiqiang Zhao Xiaoxiang Hu Ning Li 2016 A Complex Structural Variation on Chromosome 27 Leads to the Ectopic Expression of HOXB8 and the Muffs and Beard Phenotype in Chickens Archived November 5 2021 at the Wayback Machine PLoS Genetics 12 6 e1006071 doi 10 1371 journal pgen 1006071 Chickens team up to peck fox to death The Independent March 13 2019 Archived from the original on March 15 2019 Retrieved March 13 2019 Chickens gang up to kill fox Bbc co uk March 13 2019 Archived from the original on March 14 2019 Retrieved March 13 2019 AFP March 12 2019 Chickens teamed up to kill fox at Brittany farming school Theguardian com Archived from the original on March 13 2019 Retrieved March 13 2019 a b Why Do Chickens Puff up Their Feathers I 4 Reasons Explained August 8 2020 Archived from the original on June 18 2021 Retrieved June 16 2021 Top cock Roosters crow in pecking order Archived from the original on January 15 2018 Retrieved January 14 2018 Evans Christopher S Evans Linda Marler Peter July 1993 On the meaning of alarm calls functional reference in an avian vocal system Animal Behaviour 46 1 23 38 doi 10 1006 anbe 1993 1158 S2CID 53165305 Cock crowing contest recognised as National Heritage in Belgium Archived November 23 2020 at the Wayback Machine Stefaan De Groote Het Nieuwsblad 27 June 2011 in Dutch Accessed October 2015 a b c Grandin Temple Johnson Catherine 2005 Animals in Translation New York City Scribner pp 69 71 ISBN 978 0 7432 4769 6 Cheng Kimberly M Burns Jeffrey T August 1988 Dominance Relationship and Mating Behavior of Domestic Cocks A Model to Study Mate Guarding and Sperm Competition in Birds The Condor 90 3 697 704 doi 10 2307 1368360 JSTOR 1368360 Sherwin C M Nicol C J 1993 Factors influencing floor laying by hens in modified cages Applied Animal Behaviour Science 36 2 3 211 222 doi 10 1016 0168 1591 93 90011 d Ali A Cheng K M 1985 Early egg production in genetically blind rc rc chickens in comparison with sighted Rc rc controls Poultry Science 64 5 789 794 doi 10 3382 ps 0640789 PMID 4001066 Briskie J V R Montgomerie 1997 Sexual Selection and the Intromittent Organ of Birds Journal of Avian Biology 28 1 73 86 doi 10 2307 3677097 JSTOR 3677097 Bain M M Nys Y Dunn I C May 3 2016 Increasing persistency in lay and stabilising egg quality in longer laying cycles What are the challenges British Poultry Science Taylor amp Francis 57 3 330 338 doi 10 1080 00071668 2016 1161727 ISSN 0007 1668 PMC 4940894 PMID 26982003 S2CID 17842329 Young John J Tabin Clifford J September 2017 Saunders s framework for understanding limb development as a platform for investigating limb evolution Developmental Biology 429 2 401 408 doi 10 1016 j ydbio 2016 11 005 PMC 5426996 PMID 27840200 Scientists Find Chickens Retain Ancient Ability to Grow Teeth Archived June 20 2008 at the Wayback Machine Ammu Kannampilly ABC News February 27 2006 Retrieved October 1 2007 International Chicken Genome Sequencing Consortium December 9 2004 Sequence and comparative analysis of the chicken genome provide unique perspectives on vertebrate evolution Nature 432 7018 695 716 Bibcode 2004Natur 432 695C doi 10 1038 nature03154 PMID 15592404 Gregory T Ryan September 2005 Synergy between sequence and size in Large scale genomics Nature Reviews Genetics 6 9 699 708 doi 10 1038 nrg1674 Warren Wesley C Hillier LaDeana W Tomlinson Chad Minx Patrick Kremitzki Milinn Graves Tina Markovic Chris Bouk Nathan Pruitt Kim D Thibaud Nissen Francoise Schneider Valerie Mansour Tamer A Brown C Titus Zimin Aleksey Hawken Rachel Abrahamsen Mitch Pyrkosz Alexis B Morisson Mireille Fillon Valerie Vignal Alain Chow William Howe Kerstin Fulton Janet E Miller Marcia M Lovell Peter Mello Claudio V Wirthlin Morgan Mason Andrew S Kuo Richard Burt David W Dodgson Jerry B Cheng Hans H January 2017 A New Chicken Genome Assembly Provides Insight into Avian Genome Structure G3 7 1 109 117 doi 10 1534 g3 116 035923 PMC 5217101 PMID 27852011 Zhang H Wang X T Chamba Y Ling Y Wu C X October 2008 Influences of Hypoxia on Hatching Performance in Chickens with Different Genetic Adaptation to High Altitude Poultry Science 87 10 2112 2116 doi 10 3382 ps 2008 00122 ISSN 0032 5791 PMID 18809874 Nakane Yusuke Yoshimura Takashi February 15 2019 Photoperiodic Regulation of Reproduction in Vertebrates Annual Review of Animal Biosciences Annual Reviews 7 1 173 194 doi 10 1146 annurev animal 020518 115216 ISSN 2165 8102 PMID 30332291 S2CID 52984435 Brownlie Robert Allan Brenda September 1 2010 Avian toll like receptors Cell and Tissue Research Springer 343 1 121 130 doi 10 1007 s00441 010 1026 0 ISSN 0302 766X PMID 20809414 S2CID 2877905 Pennisi Elizabeth May 24 2018 Quaillike creatures were the only birds to survive the dinosaur killing asteroid impact Science doi 10 1126 science aau2802 a b Wong G K Liu B Wang J Zhang Y Yang X Zhang Z Meng Q Zhou J Li D Zhang J Ni P Li S Ran L Li H Zhang J Li R Li S Zheng H Lin W Li G Wang X Zhao W Li J Ye C Dai M Ruan J Zhou Y Li Y He X et al December 9 2004 A genetic variation map for chicken with 2 8 million single nucleotide polymorphisms Nature 432 7018 717 722 Bibcode 2004Natur 432 717B doi 10 1038 nature03156 PMC 2263125 PMID 15592405 a b c d Lawal Raman Akinyanju Martin Simon H Vanmechelen Koen Vereijken Addie Silva Pradeepa Al Atiyat Raed Mahmoud Aljumaah Riyadh Salah Mwacharo Joram M Wu Dong Dong Zhang Ya Ping Hocking Paul M Smith Jacqueline Wragg David Hanotte Olivier December 2020 The wild species genome ancestry of domestic chickens BMC Biology 18 1 13 doi 10 1186 s12915 020 0738 1 PMC 7014787 PMID 32050971 Eriksson Jonas Larson Greger Gunnarsson Ulrika Bed hom Bertrand Tixier Boichard Michele Stromstedt Lina Wright Dominic Jungerius Annemieke Vereijken Addie Randi Ettore Jensen Per Andersson Leif February 29 2008 Identification of the Yellow Skin Gene Reveals a Hybrid Origin of the Domestic Chicken PLOS Genetics 4 2 e1000010 doi 10 1371 journal pgen 1000010 PMC 2265484 PMID 18454198 Fumihito A Miyake T Sumi S Takada M Ohno S Kondo N December 20 1994 One subspecies of the red junglefowl Gallus gallus gallus suffices as the matriarchic ancestor of all domestic breeds PNAS 91 26 12505 12509 Bibcode 1994PNAS 9112505F doi 10 1073 pnas 91 26 12505 PMC 45467 PMID 7809067 King Rick February 24 2009 Rat Attack NOVA and National Geographic Television archived from the original on August 23 2017 retrieved August 25 2017 King Rick February 1 2009 Plant vs Predator NOVA archived from the original on August 21 2017 retrieved August 25 2017 West B Zhou B X 1988 Did chickens go north New evidence for domestication J Archaeol Sci 14 5 515 533 doi 10 1016 0305 4403 88 90080 5 Al Nasser A Al Khalaifa H Al Saffar A Khalil F Albahouh M Ragheb G Al Haddad A Mashaly M June 1 2007 Overview of chicken taxonomy and domestication World s Poultry Science Journal 63 2 285 300 doi 10 1017 S004393390700147X S2CID 86734013 Wang Ming Shan et al 2020 863 genomes reveal the origin and domestication of chicken Cell Research 30 8 693 701 doi 10 1038 s41422 020 0349 y PMC 7395088 PMID 32581344 S2CID 220050312 Liu Yi Ping Wu Gui Sheng Yao Yong Gang Miao Yong Wang Luikart Gordon Baig Mumtaz Beja Pereira Albano Ding Zhao Li Palanichamy Malliya Gounder Zhang Ya Ping January 2006 Multiple maternal origins of chickens Out of the Asian jungles Molecular Phylogenetics and Evolution 38 1 12 19 doi 10 1016 j ympev 2005 09 014 PMID 16275023 Zeder Melinda A Emshwiller Eve Smith Bruce D Bradley Daniel G March 2006 Documenting domestication the intersection of genetics and archaeology Trends in Genetics 22 3 139 155 doi 10 1016 j tig 2006 01 007 PMID 16458995 a b Thomson Vicki A Lebrasseur Ophelie Austin Jeremy J Hunt Terry L Burney David A Denham Tim Rawlence Nicolas J Wood Jamie R Gongora Jaime Girdland Flink Linus Linderholm Anna Dobney Keith Larson Greger Cooper Alan April 2014 Using ancient DNA to study the origins and dispersal of ancestral Polynesian chickens across the Pacific Proceedings of the National Academy of Sciences 111 13 4826 4831 Bibcode 2014PNAS 111 4826T doi 10 1073 pnas 1320412111 PMC 3977275 PMID 24639505 Piper Philip J 2017 The Origins and Arrival of the Earliest Domestic Animals in Mainland and Island Southeast Asia A Developing Story of Complexity In Piper Philip J Matsumura Hirofumi Bulbeck David eds New Perspectives in Southeast Asian and Pacific Prehistory terra australis Vol 45 ANU Press ISBN 9781760460945 Archived from the original on November 28 2022 Retrieved May 5 2023 Meleisea Malama March 25 2004 The Cambridge History of the Pacific Islanders Cambridge University Press p 56 ISBN 9780521003544 Archived from the original on September 13 2016 Retrieved March 13 2019 via Google Books Crawford Michael H March 13 2019 Anthropological Genetics Theory Methods and Applications Cambridge University Press p 411 ISBN 9780521546973 Archived from the original on September 13 2016 Retrieved March 13 2019 via Google Books Neumann Scott March 18 2014 Study The Chicken Didn t Cross The Pacific To South America The Two Way NPR Archived from the original on May 5 2023 Retrieved May 5 2023 a b c d e CHOF The Cambridge History of Food 2000 Cambridge University Press vol 1 pp496 499 Perry Gal Lee Erlich Adi Gilboa Ayelet Bar Oz Guy August 11 2015 Earliest economic exploitation of chicken outside East Asia Evidence from the Hellenistic Southern Levant Proceedings of the National Academy of Sciences 112 32 9849 9854 Bibcode 2015PNAS 112 9849P doi 10 1073 pnas 1504236112 PMC 4538678 PMID 26195775 Karayanis Dean Karayanis Catherine March 13 2019 Regional Greek Cooking Hippocrene Books p 176 ISBN 9780781811460 Archived from the original on September 13 2016 Retrieved March 13 2019 via Google Books Chiffolo Anthony F Hesse Rayner W March 13 2019 Cooking with the Bible Biblical Food Feasts and Lore Greenwood Publishing Group p 207 ISBN 9780313334108 Archived from the original on September 13 2016 Retrieved March 13 2019 via Google Books Perry Gal L Erlich A Gilboa A Bar Oz G 2015 Earliest economic exploitation of chicken outside East Asia Evidence from the Hellenistic Southern Levant Proceedings of the National Academy of Sciences of the United States of America 112 32 9849 9854 Bibcode 2015PNAS 112 9849P doi 10 1073 pnas 1504236112 PMC 4538678 PMID 26195775 We further argue that the earliest secure evidence for economic exploitation of chickens in Europe dates to the first century B C E and therefore is predated by the finds in the Southern Levant by at least a century Brown Marley September October 2017 Fast Food Archaeology 70 5 18 ISSN 0003 8113 Archived from the original on July 25 2019 Retrieved July 25 2019 Borrell Brendan June 1 2007 DNA reveals how the chicken crossed the sea Nature 447 7145 620 621 Bibcode 2007Natur 447R 620B doi 10 1038 447620b PMID 17554271 S2CID 4418786 Storey A A Ramirez J M Quiroz D Burley D V Addison D J Walter R Anderson A J Hunt T L Athens J S Huynen L Matisoo Smith E A June 19 2007 Radiocarbon and DNA evidence for a pre Columbian introduction of Polynesian chickens to Chile Proceedings of the National Academy of Sciences 104 25 10335 10339 Bibcode 2007PNAS 10410335S doi 10 1073 pnas 0703993104 PMC 1965514 PMID 17556540 Wilford John Noble June 5 2007 First Chickens in Americas Were Brought From Polynesia The New York Times Archived from the original on June 7 2007 Gongora Jaime Rawlence Nicolas J Mobegi Victor A Jianlin Han Alcalde Jose A Matus Jose T Hanotte Olivier Moran Chris Austin J Ulm Sean Anderson Atholl Larson Greger Cooper Alan 2008 Indo European and Asian origins for Chilean and Pacific chickens revealed by mtDNA PNAS 105 30 10308 10313 Bibcode 2008PNAS 10510308G doi 10 1073 pnas 0801991105 PMC 2492461 PMID 18663216 Thomson Vicki A Lebrasseur Ophelie Austin Jeremy J Hunt Terry L Burney David A Denham Tim Rawlence Nicolas J Wood Jamie R Gongora Jaime Girdland Flink Linus Linderholm Anna Dobney Keith Larson Greger Cooper Alan April 1 2014 Using ancient DNA to study the origins and dispersal of ancestral Polynesian chickens across the Pacific Proceedings of the National Academy of Sciences 111 13 4826 4831 Bibcode 2014PNAS 111 4826T doi 10 1073 pnas 1320412111 PMC 3977275 PMID 24639505 Jones E K M Prescott N B 2000 Visual cues used in the choice of mate by fowl and their potential importance for the breeder industry World s Poultry Science Journal 56 2 127 138 doi 10 1079 WPS20000010 S2CID 86481908 About chickens Compassion in World Farming Ciwf org uk Archived from the original on April 26 2017 Retrieved April 25 2017 Fereira John Poultry Slaughter Annual Summary usda mannlib cornell edu Archived from the original on April 26 2017 Retrieved April 25 2017 Fereira John Chickens and Eggs Annual Summary usda mannlib cornell edu Archived from the original on April 26 2017 Retrieved April 25 2017 Towards Happier Meals In A Globalized World World Watch Institute Archived from the original on May 29 2014 Retrieved May 29 2014 Ilea Ramona Cristina April 2009 Intensive Livestock Farming Global Trends Increased Environmental Concerns and Ethical Solutions Journal of Agricultural and Environmental Ethics 22 2 153 167 doi 10 1007 s10806 008 9136 3 S2CID 154306257 Tilman David Cassman Kenneth G Matson Pamela A Naylor Rosamond Polasky Stephen August 2002 Agricultural sustainability and intensive production practices Nature 418 6898 671 677 Bibcode 2002Natur 418 671T doi 10 1038 nature01014 PMID 12167873 S2CID 3016610 Broiler Chickens Fact Sheet Animals Australia Animalsaustralia org Archived from the original on July 12 2010 Retrieved August 29 2010 UK Egg Industry Data Official Egg Info Egginfo co uk Archived from the original on December 30 2016 Retrieved April 25 2017 Glenday Craig April 26 2011 Guinness World Records 2011 Mass Market Paperback p 286 ISBN 978 0440423102 a b Browne Anthony March 10 2002 Ten weeks to live The Guardian London Archived from the original on May 16 2008 Retrieved April 28 2010 Patwardhan D King A 2011 Review feed withdrawal and non feed withdrawal moult World s Poultry Science Journal 67 2 253 268 doi 10 1017 s0043933911000286 S2CID 88353703 Webster A B 2003 Physiology and behavior of the hen during induced moult Poultry Science 82 6 992 1002 doi 10 1093 ps 82 6 992 PMID 12817455 Molino A B Garcia E A Berto D A Pelicia K Silva A P Vercese F 2009 The Effects of Alternative Forced Molting Methods on The Performance and Egg Quality of Commercial Layers Brazilian Journal of Poultry Science 11 2 109 113 doi 10 1590 s1516 635x2009000200006 Yousaf M Chaudhry A S March 1 2008 History changing scenarios and future strategies to induce moulting in laying hens PDF World s Poultry Science Journal 64 1 65 75 doi 10 1017 s0043933907001729 S2CID 34761543 Archived PDF from the original on November 24 2020 Retrieved October 23 2020 Fly Colin July 27 2007 Some homeowners find chickens all the rage Chicago Tribune permanent dead link Pollack Fusi Mindy December 16 2004 Cooped up in suburbia Boston Globe Archived from the original on March 4 2016 Retrieved June 4 2020 Kreilkamp Ivan November 25 2020 How Caring for Backyard Chickens Stretched My Emotional Muscles The New York Times Archived from the original on November 25 2020 Boone Lisa August 27 2017 Chickens will become a beloved pet just like the family dog Los Angeles Times Archived from the original on April 2 2019 Retrieved April 3 2019 Barras Colin Despite what you might think chickens are not stupid www bbc com Archived from the original on June 5 2021 Retrieved September 6 2020 United Poultry Concerns Providing a Good Home for Chickens Archived from the original on June 5 2009 Retrieved May 4 2009 Choosing Your Chickens Clucks and Chooks Archived from the original on July 30 2009 Is It Safe To Feed My Chickens Table Scraps The Happy Chicken Coop October 21 2021 Archived from the original on October 4 2022 Retrieved October 5 2022 gamecock Merriam Webster Online Dictionary Archived August 18 2017 at the Wayback Machine first use of word 1646 Should cockfighting be outlawed in Oklahoma CNN November 26 2002 Archived from the original on June 19 2009 Retrieved August 17 2009 Sherman David M 2002 Tending Animals in the Global Village Blackwell Publishing 46 ISBN 0 683 18051 7 Joe G Berry Artificial Incubation Oklahoma Cooperative Extension Service Oklahoma State University Archived PDF from the original on June 4 2010 Retrieved September 29 2010 Phillip J Clauer Incubating Eggs PDF Virginia Cooperative Extension Service Virginia State University Archived PDF from the original on June 13 2010 Retrieved October 1 2010 White Tiffany M Gilden Donald H Mahalingam Ravi October 2001 An Animal Model of Varicella Virus Infection Brain Pathology 11 4 475 479 doi 10 1111 j 1750 3639 2001 tb00416 x PMC 8098339 PMID 11556693 S2CID 26073177 Forget dogs and cats The most pampered pets of the moment might be our backyard chickens USA TODAY Archived from the original on April 3 2019 Retrieved April 3 2019 CDC March 18 2019 Keeping Backyard Poultry Centers for Disease Control and Prevention Archived from the original on April 1 2019 Retrieved April 3 2019 Crop bound Archived from the original on October 26 2010 Infectious Bronchitis Virus Classical and Variant Strains Archived from the original on October 5 2021 Retrieved June 11 2022 Necrotic Enteritis Archived from the original on December 16 2010 Overview of Omphalitis in Poultry Merck Veterinary Manual Archived from the original on January 13 2017 Retrieved January 10 2017 Clucks and Chooks guide to keeping chickens Henkeeping co uk Archived from the original on January 15 2010 Retrieved October 26 2009 Merck Veterinary Manual Archived from the original on March 11 2007 Retrieved January 10 2007 a b Oladokun Samson Adewole Deborah I October 1 2022 Biomarkers of heat stress and mechanism of heat stress response in Avian species Current insights and future perspectives from poultry science Journal of Thermal Biology 110 103332 doi 10 1016 j jtherbio 2022 103332 PMID 36462852 S2CID 252361675 Alhenaky Alhanof Abdelqader Anas Abuajamieh Mohannad Al Fataftah Abdur Rahman November 3 2017 The effect of heat stress on intestinal integrity and Salmonella invasion in broiler birds Journal of Thermal Biology 70 Pt B 9 14 doi 10 1016 j jtherbio 2017 10 015 PMID 29108563 Kuter Eren Cengiz Ozcan Koksal Bekir Hakan Sevim Omer Tatli Onur Ahsan Umair Guven Gulsen Onol Ahmet Gokhan Bilgili Sacit F December 28 2022 Litter quality and incidence and severity of footpad dermatitis in heat stressed broiler chickens fed supplemental zinc Livestock Science 267 1491 1499 doi 10 1016 j livsci 2022 105145 S2CID 254914487 Xu Yongjie Lai Xiaodan Li Zhipeng Zhang Xiquan Luo Qingbin November 1 2018 Effect of chronic heat stress on some physiological and immunological parameters in different breed of broilers Poultry Science 97 11 4073 4082 doi 10 3382 ps pey256 PMC 6162357 PMID 29931080 Orhan Cemal Tuzcu Mehmet Deeh Patrick Brice Defo Sahin Nurhan Komorowski James R Sahin Kazim August 21 2018 Organic Chromium Form Alleviates the Detrimental Effects of Heat Stress on Nutrient Digestibility and Nutrient Transporters in Laying Hens Biological Trace Element Research 189 2 529 537 doi 10 1007 s12011 018 1485 9 PMID 30132119 S2CID 255452740 Sahin N Hayirli A Orhan C Tuzcu M Akdemir F Komorowski J R Sahin K December 11 2019 Effects of the supplemental chromium form on performance and oxidative stress in broilers exposed to heat stress Poultry Science 96 12 4317 4324 doi 10 3382 ps pex249 PMID 29053811 S2CID 10630678 Untea Arabela Elena Varzaru Iulia Turcu Raluca Paula Panaite Tatiana Dumitra Saracila Mihaela October 13 2021 The use of dietary chromium associated with vitamins and minerals synthetic and natural source to improve some quality aspects of broiler thigh meat reared under heat stress condition Italian Journal of Animal Science 20 1 1491 1499 doi 10 1080 1828051X 2021 1978335 S2CID 244583811 Ding Kang Ning Lu Meng Han Guo Yan Na Liang Shao Shan Mou Rui Wei He Yong Ming He Tang Lu Ping December 14 2022 Resveratrol relieves chronic heat stress induced liver oxidative damage in broilers by activating the Nrf2 Keap1 signaling pathway Ecotoxicology and Environmental Safety 249 114411 doi 10 1016 j ecoenv 2022 114411 PMID 36525949 S2CID 254723325 Sahin K Sahin N Kucuk O Hayirli A Prasad A S October 1 2009 Role of dietary zinc in heat stressed poultry A review Poultry Science 88 10 2176 2183 doi 10 3382 ps 2008 00560 PMID 19762873 El Tarabany Mahmoud S August 27 2016 Effect of thermal stress on fertility and egg quality of Japanese quail Journal of Thermal Biology 61 38 43 doi 10 1016 j jtherbio 2016 08 004 PMID 27712658 Bilal Rana Muhammad Hassan Faiz ul Farag Mayada R Nasir Taquir Ali Ragni Marco Ahsan Umair Guven Gulsen April 20 2021 Thermal stress and high stocking densities in poultry farms Potential effects and mitigation strategies Journal of Thermal Biology 99 102944 doi 10 1016 j jtherbio 2021 102944 PMID 34420608 S2CID 233555119 Kucuk O January 10 2008 Zinc in a Combination with Magnesium Helps Reducing Negative Effects of Heat Stress in Quails Biological Trace Element Research 123 1 3 144 153 doi 10 1007 s12011 007 8083 6 PMID 18188513 S2CID 24775551 de Carvalho Curi T M R de Alencar Naas I da Silva Lima N D Martinez A A G January 24 2022 Climate change impact on Brazilian broiler production cost a simulation study International Journal of Environmental Science and Technology 19 11 10589 10598 doi 10 1007 s13762 021 03893 z S2CID 246211499 External links nbsp Media related to Chickens at Wikimedia Commons nbsp The dictionary definition of cockerel at Wiktionary nbsp Data related to Gallus gallus domesticus at Wikispecies Retrieved from https en wikipedia org w index php title Chicken amp oldid 1183671045, wikipedia, wiki, book, books, library,

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