Chicken

? Chicken Conservation status: Domesticated
A Bantam rooster
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Aves Order: Galliformes Family: Phasianidae Genus: Gallus Species: G. gallus
Binomial name
Gallus gallus

A chicken (Gallus gallus) is a type of domesticated bird which is often raised as a type of poultry. It is believed to be descended from the wild Asian Red Junglefowl.

Chickens are the most common bird in the world. The population in 2003 was 24 billion, according to the Firefly Encyclopedia of Birds.

General biology and habitat

Male chickens are known as roosters (in the U.S., Canada and Australia), cocks, or cockerels if they are young. Female chickens are known as hens, or 'chooks' in Australasian English. Roosters can usually be differentiated from hens by their striking plumage, marked by long flowing tails and bright pointed feathers on their necks. However in some breeds, such as the Sebright, the cock only has slightly pointed neck feathers, and the identification must be made by looking at the comb. Both the male and female have distinctive wattles and combs. These organs help to cool the bird by redirecting bloodflow to the skin. In males, the combs are often more prominent, though this is not the case in all varieties.

Chickens have a flesh crest on their heads called a comb and a fleshy piece of hanging skin under their beak called a wattle. Chickens are often kept in gardens, not just in farms, and can make loving and gentle pets.

Chickens are omnivores and will feed on small seeds, herbs and leaves, grubs, insects and even small mammals like mice, if they can get them. Domestic chickens are typically fed commercially prepared feed that includes a protein source as well as grains. Chickens often scratch at the soil to get at adult insects and larva or seed. Incidents of cannibalism can occur when a curious bird pecks at a pre-existing wound or from over-crowding. This is exacerbated in close quarters. In commercial production this is controlled with chick " debeaking" (removal of 2/3 of the top half and 1/3 of the lower half of the beak). This " debeaking" process may be painful for chickens because their beaks are filled with nerve endings.

Domestic chickens are not capable of flying for long distances, although they are generally capable of flying for short distances such as over fences. Chickens will sometimes fly simply in order to explore their surroundings, but will especially fly in an attempt to flee when they perceive danger. Because of the risk of flight, chickens raised in the open air generally have one of their wings clipped by the breeder — the tips of the longest feathers on one of the wings are cut, resulting in unbalanced flight which the bird cannot sustain for more than a few meters. ( more on wing clipping)

Chickens are gregarious birds and live together as a flock. 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 access to food 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.

Chickens will try to lay in nests that already contain eggs, and have been known to move eggs from neighbouring nests into their own. Some farmers use fake eggs made from plastic or stone to encourage hens to lay in a particular location. 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 can also be extremely stubborn about always laying in the same location. It is not unknown for two (or more) hens to 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.

Contrary to popular belief, roosters may crow at anytime of the day. Their crowing - a loud and sometimes shrill call - is a territorial signal to other roosters.

Chickens are domesticated descendents of the red junglefowl, which is biologically classified as the same species.

Courting

When a rooster finds food he may call the other chickens to eat it first. He does this by clucking in a high pitch as well as picking up and dropping the food. This is part of chicken courting ritual. When a hen is used to coming to his "call" the rooster may mount the hen and fertilize her egg.

Going broody

Sometimes a hen will stop laying and instead will focus on the incubation of eggs, a state that is commonly known as going broody. A broody chicken will sit fast on the nest, and protest if disturbed or removed, and will rarely leave the nest to eat, drink, or dust bathe. While broody, the hen keeps the eggs at a constant temperature and humidity, as well as turning the eggs regularly.

At the end of the incubation period, which is an average of 21 days, the eggs (if fertilized) will hatch, and the broody hen will take care of her young. Since individual eggs do not all hatch at exactly the same time (the chicken can only lay one egg approximately every 25 hours), the hen will usually stay on the nest for about two days after the first egg hatches. During this time, the newly-hatched chicks live off the egg yolk they absorb just before hatching. The hen can hear the chicks peeping inside the eggs, and will gently cluck to encourage them to break out of their shells. If the eggs are not fertilized and do not hatch, the hen will eventually grow tired of being broody and leave the nest.

Modern egg-laying breeds rarely go broody, and those that do often stop part-way through the incubation cycle. Some breeds, such as the Cochin, Cornish and Silkie, regularly go broody and make excellent mothers.

Artificial incubation

Chicken egg incubation can successfully occur artificially as well. Nearly all chicken eggs will hatch after 21 days of good conditions - 98-100 degrees fahrenheit (38° C) and around 65% relative humidity (may decrease to 55% in the last three days of incubation.) 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 usually small boxes ( styrofoam incubators are popular) and hold 50 eggs. Eggs must be turned three to five times each day, rotating at least 90 degrees. If eggs aren't turned, the embryo inside will stick to the shell and likely will be born with physical defects. This process is natural: hens will stand up three to five times a day and shift the eggs around with their beak.

Chickens as food

Chickens serve as one of the most common meats in the world, and are frequently prepared as food in a large number of ways. There is significant variation in cooking methods amongst cultures; historically common methods include roasting, baking, and frying. Today, chickens are also cooked by deep frying and prepared as fast food such as chicken nuggets. Modern varieties of chicken, such as the Cornish Cross, are bred specifically for meat production, with an emphasis placed on the ratio of feed to meat produced by the animal. In Chinese culinary culture, chicken is highly-valued, as in the phrase "無雞不歡" (roughly translates as 'no chicken, no satisfaction').

Chickens raised specifically for meat are called broilers. In the United States, broilers are typically butchered at a young age. Modern Cornish Cross hybrids, for example, are butchered as early as 8 weeks for fryers and 12 weeks for roasting birds. Typically, the muscle tissue (breast, legs, thigh, etc), livers, and gizzard are processed for food. Chicken feet are less commonly eaten. The head, internal organs such as the lungs and intestines, and feathers are typically discarded or ground into a protein meal for inclusion in other animal feeds, although Chinese cuisines may retain the whole bird on the dish (with the head), depending on the dish.

Capons ( castrated cocks) produce more and fattier meat than normal cocks. For this reason, they are considered a delicacy and were particularly popular in the Middle Ages. Caponizing a cock, unlike castrating a steer or pig, requires delicate surgery and is an art almost lost today. The cock's testicles lie within its body cavity. To remove them requires special equipment and skill. The person caponizing the rooster must make precise and specialized cuts within the abdomen of the rooster. Infection and potential damage to the bird are possible should an unskilled individual perform the surgery.

Chicken eggs, produced by pullets and laying hens, are also very commonly eaten. The chicken egg is the most commonly eaten bird egg in the world. Hens may lay fertile or infertile eggs. Hens will continue to lay even if a rooster is not present, though these will not be viable. There is no difference in the nutritional value between a fertilized and unfertilized egg. Modern breeding techniques focusing on feed-to-egg conversion ratios have increased the number of eggs a hen can lay. Modern egg chickens are typically derived from the early Leghorn varieties. When the egg is laid, the egg is not soft but has a hard shell. This shell protects the egg's contents, making it a food source that is easily transported and stored. Nutritionally, the egg provides a rich source of protein and vitamins. Recent concerns over cholesterol, however, have caused many to question the place of eggs in the human diet.

Some chicken breeds are raised for both meat and egg production. Typically heavy breeds, these are primarily grown by small farmers or hobbyists. These include breeds such as the Wyandotte, Brahma, or Barred Rock.

Chickens as pets

In Asia, chickens with striking plumage have long been kept for ornamental purposes, including feather-footed varieties such as the Cochin and Silkie from China and the extremely long-tailed (Phoenix) from Japan. Asian ornamental varieties were imported into the United States and Great Britain in the late 1800s. Poultry fanciers then began keeping these ornamental birds for exhibition, a practice that continues today. From these Asian breeds, distinctive American varieties of chickens have been developed.

Today, some cities in the United States still allow residents to keep live chickens as pets, although the practice is quickly disappearing. Individuals in rural communities commonly keep chickens for both ornamental and practical value. Some communities ban only roosters, allowing the quieter hens. Many zoos use chickens instead of insecticides to control insect populations.

Growing chickens can easily be tamed by feeding them a special treat such as mealworms in the palm of one's hand, and by being with them for at least ten minutes daily when they are young.

Chickens in agriculture

In the United States, chickens were once raised primarily on the family farm. Prior to about 1930, chicken was served for primarily on special occasions or on Sunday as the birds were typically more valued for their eggs than meat. Excess roosters or non-productive hens would be culled from the flock first for butchering. As cities developed and markets sprung up across the nation, live chickens from local farms could often be seen for sale in crates outside the market, to be butchered and cleaned onsite by the butcher.

With the advent of refrigeration, poultry production changed dramatically. Large farms and packing plants emerged that could grow birds by the thousands. Adult chickens could be sent to factories for butchering and processing into pre-packaged commercial products to be frozen or shipped fresh to markets or wholesalers. Large farms or factories could be established devoted solely to egg production and packaging. Once a meat consumed only occasionally, the common availability has made chicken a common and significant meat product within developed nations. Growing concerns over cholesterol in the 1980s and 1990s further resulted in increased consumption.

Similarly, egg production also changed with the development of automation and refrigeration. Today, eggs are grown on factory farms in highly controlled settings. Special varieties of chickens are fed special diets high in calcium and protein to stimulate maximum egg production. Chickens are exposed to artificial light cycles to stimulate egg production year-round. In addition, it is a common practice to force chickens to molt through the careful manipulation of light and the amount of food they receive in order to further increase egg production.

Often, people in Third World Countries such as India, keep chickens for their produce, meat and for their company.

Issues with mass production

Many animal advocates object to killing chickens for food or object to the factory farm conditions under which they are raised. Commercial chicken production often involves raising the birds in large crowded rearing sheds that prevent the chickens from engaging in many of their natural behaviours. In 2004 8.9 billion chickens were slaughtered in the United States [1].

Another animal welfare issue is the use of genetic selection to create heavy large-breasted birds, which can lead to crippling leg disorders and heart failure for some of the birds. In addition, many scientists have raised concerns that companies growing one variety of bird for eggs or meat are much more susceptible to potentially devastating disease. For this reason, many scientists are promoting the conservation of heritage breeds to retain genetic diversity in the species.

Cockfighting

Male chickens are known as cocks (in most countries), cockerels (if younger than one year) or roosters (primarily in the US and Canada). Their natural inclination to fight has been exploited in staged fights, sometimes with a metal spike added to or replacing the natural spurs. Most countries have banned cockfighting, but it is still legal in two U.S. states, New Mexico and Louisiana, and is common in Southeast Asia.

The University of South Carolina's athletic mascot is the fighting gamecock, a designation which has in recent years provoked criticism from some animal-rights activists.

Cockfighting was popular in ancient Greece. According to tradition, it was introduced in Athens by Themistokles as a public spectacle. Fighting roosters were fed garlic and onions to increase their aggression. In ancient Greece, the gift of a fighting rooster among men is said to have been a common way to initiate a homosexual relationship. Gems often show a rooster combined with Eros, the god of love.

Sometimes it has a religious significance, as in Bali, where the shed blood is seen as cleansing.

Chicken diseases

• Aspergillosis
• Avian influenza (bird flu)
• Blackhead disease
• Botulism
• Cage Layer Fatigue
• Coccidiosis
• Colds
• Crop bound
• Egg bound
• Erysipelas
• Fatty Liver Hemorrhagic Syndrome
• Fowl Cholera
• Fowl pox
• Fowl Typhoid
• Gapeworms
• Infectious Bronchitis
• Infectious Bursal Disease ( Gumboro)
• Infectious Coryza
• Lymphoid Leucosis
• Marek's disease
• Moniliasis
• Mycoplasmas
• Newcastle disease
• Necrotic Enteritis
• Omphalitis (Mushy chick disease)
• Psittacosis
• Pullorum ( Salmonella)
• Scaly leg
• Squamous cell carcinoma
• Tibial dyschondroplasia
• Toxoplasmosis
• Ulcerative Enteritis

Chickens are also susceptible to parasites, including lice, mites, ticks, fleas, and intestinal Worms.

Chickenpox is a disease of humans, not chickens.

Chickens in religion

In India, the Rooster is an insignia of Karthikeya, son of Lord Shiva, the God of Destruction. Karthikeya is known by his popular names of Murugan and Subrahmanya in the southern part of the country.

In Indonesia the chicken has great significance during the Hindu cremation ceremony. A chicken is a channel for evil spirits which may be present during the ceremony. A chicken is tethered by the leg and kept present at the ceremony for the duration to ensure that any evil spirits present during the ceremony go into the chicken and not the family members present. The chicken is then taken home and returns to its normal life. It is not treated in any special way or slaughtered after the ceremony.

In ancient Greece, the chicken was not normally used for sacrifices, perhaps because it was still considered an exotic animal. Because of its valour, cocks are found as attributes of Ares, Heracles and Athena. The Greeks believed that even lions were afraid of cocks. Several of Aesop's Fables reference this belief.

In the cult of Mithras, the cock was a symbol of the divine light and a guardian against evil.

In the Bible, Jesus prophesied the betrayal by Peter: "And he said, I tell thee, Peter, the cock shall not crow this day, before that thou shalt thrice deny that thou knowest me." ( Luke 22:43) Thus it happened (Luke 22:61), and Peter cried bitterly. This made the cock a symbol for both vigilance and betrayal.

Earlier, Jesus compares himself to a mother hen, when talking about Jerusalem: "How often would I have gathered thy children together, even as a hen gathereth her chickens under her wings, and ye would not!" ( Matthew 23:37; also Luke 13:34).

In many Central European folk tales, the devil is believed to flee at the first crowing of a cock.

In some sects of Orthodox Judaism a chicken is slaughtered on the afternoon before Yom Kippur (Day of Atonement) in a ceremony called kappores. Although not actually a sacrifice in the biblical sense, the death of the chicken reminds the penitent sinner that his or her life is in God's hands. A woman brings a hen to be slaughtered, a man brings a rooster. The meat is donated to the poor.

The Talmud speaks of learning "courtesy toward one's mate" from the rooster. This might refer to the fact that, when a rooster finds something good to eat, he calls his hens to eat first.

The chicken is one of the Zodiac symbols of the Chinese calendar. Also in Chinese religion, a cooked chicken as a religious offering is usually limited to ancestor veneration and worship of village deities. Vegetarian deities such as Buddha are not one of the recipients of such offerings. Under some observations, an offering of chicken is present with "serious" prayer (while roasted pork is offered during a joyous celebration).

History

The first pictures of chickens in Europe are found on Corinthian pottery of the 7th century BC. The poet Cratinus (mid- 5th century BC, according to the later Greek author Athenaeus) calls the chicken "the Persian alarm". In Aristophanes's comedy The Birds ( 414 BC) a chicken is called "the Median bird", which points to an introduction from the East. Pictures of chickens are found on Greek red figure and black-figure pottery.

In ancient Greece, chickens were still rare and were a rather prestigious food for symposia. Delos seems to have been a centre of chicken breeding.

An early domestication of chickens in Southeast Asia is probable, since the word for domestic chicken (*manuk) is part of the reconstructed Proto-Austronesian language (see Austronesian languages). Chickens, together with dogs and pigs, were the domestic animals of the Lapita culture, the first Neolithic culture of Oceania.

Chickens were spread by Polynesian seafarers and reached Easter Island in the 12th century AD, where they were the only domestic animal, with the possible exception of the Polynesian Rat (Rattus exulans). They were housed in extremely solid chicken coops built from stone. Traveling as cargo on trading boats, they reached the Asian continent via the islands of Indonesia and from there spread west to Europe and western Asia.

Chickens in Ancient Rome

The Romans used chickens for oracles, both when flying ("ex avibus") and when feeding ("auspicium ex tripudiis"). The hen ("gallina") gave a favourable omen ("auspicium ratum"), when appearing from the left (Cic.,de Div. ii.26), like the crow and the owl.

For the oracle "ex tripudiis" according to Cicero (Cic. de Div. ii.34), any bird could be used, but normally only chickens ("pulli") were consulted. The chickens were cared for by the pullarius, who opened their cage and fed them pulses or a special kind of soft cake when an augury was needed. If the chickens stayed in their cage, made noises ("occinerent"), beat their wings or flew away, the omen was bad; if they ate greedily, the omen was good.

In 249 BC, the Roman general Publius Claudius Pulcher had his chickens thrown overboard when they refused to feed before the battle of Drepana, saying "If they won't eat, perhaps they will drink." He promptly lost the battle against the Carthaginians and 93 Roman ships were sunk. Back in Rome, he was tried for impiety and heavily fined.

In 161 BC a law was passed in Rome that forbade the consumption of fattened chickens. It was renewed a number of times, but does not seem to have been successful. Fattening chickens with bread soaked in milk was thought to give especially delicious results. The Roman gourmet Apicius offers 17 recipes for chicken, mainly boiled chicken with a sauce. All parts of the animal are used: the recipes include the stomach, liver, testicles and even the pygostyle (the fatty "tail" of the chicken where the tail feathers attach).

The Roman author Columella gives advice on chicken breeding in his eighth book of his treatise on agriculture. He identifies Tanagrian, Rhodic, Chalkidic and Median (commonly misidentified as Melian) breeds, which have an impressive appearance, a quarrelsome nature and were used for cockfighting by the Greeks. For farming, native (Roman) chickens are to be preferred, or a cross between native hens and Greek cocks. Dwarf chickens are nice to watch because of their size but have no other advantages.

Per Columella, the ideal flock consists of 200 birds, which can be supervised by one person if someone is watching for stray animals. White chickens should be avoided as they are not very fertile and are easily caught by eagles or goshawks. One cock should be kept for five hens. In the case of Rhodian and Median cocks that are very heavy and therefore not much inclined to sex, only three hens are kept per cock. The hens of heavy fowls are not much inclined to brood; therefore their eggs are best hatched by normal hens. A hen can hatch no more than 15-23 eggs, depending on the time of year, and supervise no more than 30 hatchlings. Eggs that are long and pointed give more male, rounded eggs mainly female hatchlings.

Per Columella, Chicken coops should face southeast and lie adjacent to the kitchen, as smoke is beneficial for the animals. Coops should consist of three rooms and possess a hearth. Dry dust or ash should be provided for dust-baths.

According to Columella, chicken should be fed on barley groats, small chick-peas, millet and wheat bran, if they are cheap. Wheat itself should be avoided, it is harmful to the birds. Boiled ryegrass (Lollium sp.) and the leaves and seeds of alfalfa (Medicago sativa L.) can be used as well. Grape marc can be used, but only when the hens stop laying eggs, that is, about the middle of November; otherwise eggs are small and few. When feeding grape marc, it should be supplemented with some bran. Hens start to lay eggs after the winter solstice, in warm places around the first of January, in colder areas in the middle of February. Parboiled barley increases their fertility; this should be mixed with alfalfa leaves and seeds, or vetches or millet if alfalfa is not at hand. Free-ranging chickens should receive two cups of barley daily.

Columella advises farmers to slaughter hens that are older than three years, because they no longer produce sufficient eggs. Capons were produced by burning out their spurs with a hot iron. The wound was treated with potter's chalk.

For the use of poultry and eggs in the kitchens of ancient Rome see Roman eating and drinking.

Famous chickens

Real chickens

• Mike the Headless Chicken

Fictional chickens

• Alecto and Galina, in Clemens Brentano's "The Tale of Gockel, Hinkel, and Gackeleia."
• Billina the talking hen from L. Frank Baum's Ozma of Oz
• Chanticleer, the rooster from Geoffrey Chaucer's The Canterbury Tales ("The Nun's Priest's Tale")
• Chicken, from the Cow and Chicken cartoon series
• Chicken Boo, from Animaniacs
• Chicken Little, the chicken that thought the sky was falling when an acorn landed on its head.
• Foghorn Leghorn, the rooster and Looney Tunes character
• Le coq d'or (The Golden Cockerel) opera by Rimsky-Korsakov, with a magical cock that is supposed to crow to warn the king of advancing enemies.
• Le galline penseuse of Luigi Malerba (Einaudi, 1980).
• Ginger, the protagonist of the movie Chicken Run
• The Goose that Laid the Golden Egg was originally a chicken in some older versions.
• The Little Red Hen, who asked everyone in the barnyard to help bake bread.
• The Rooster Prince is a parable written by Rabbi Nachman of Breslov, in which a prince goes insane and believes himself to be a rooster (in some English translations of the tale, the species of bird is a turkey).
• The San Diego Chicken
• The Subservient Chicken, part of a viral marketing promotion.
• Lord Chicken the Great; see Leongatha.
• Gyro Gearloose, a Disney character and inventor.
• Mega-Ultra Chicken is a legendary chicken raised from the dead by Frylock in Aqua Teen Hunger Force
• Roy, Booker and Sheldon from U.S. Acres
• King Chicken, from Duckman

Mythical creatures with chicken-like anatomy

1. The hut of the Russian witch Baba Yaga moves on chicken feet
2. The demon Abraxas, often depicted on " Gnostic gems" has a cock's head, the upper body of a man, while his lower part is formed by a snake. He often holds a whip.
3. The Basilisk, an animal who kills with a single glance and poisons wells, was hatched by a toad from a cock's egg.
4. The cockatrice.

Chicken as symbol

• France national rugby union team
• The Rhodesia (now Zimbabwe) independent party ZANU party used a chicken as a symbol, since a majority of the black Rhodesian citizens are analphabetical.
• The mascot of the English Premiership team Tottenham Hotspur is a cockerel.
• The standard of Sir Robin from Monty Python and the Holy Grail is a chicken.
• Town of Denizli in Republic of Turkey is symbolized by a cock.