The chicken (Gallus gallus domesticus) is a domesticated red junglefowl species that are originally from Southeast Asia. They have also partially hybridized with other wild species of junglefowls (the grey junglefowl, Ceylon junglefowl, and green junglefowl). 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 are layers.
Description & appearance
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. The identification can be made by looking at the comb, or eventually from 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 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 which causes extra feathering under the chicken's face, giving the appearance of a beard.
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. 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. 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. Diet
Chickens are omnivores. In the wild, they often scratch at the soil to search for seeds, insects, and even animals as large as lizards, small snakes, or sometimes young mice. Reproduction, breeding & chicks
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. The dance triggers a response in the hen and when she responds to his call, the rooster may mount the hen and proceed with the mating.
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.
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. 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.
Fertile chicken eggs hatch at the end of the incubation period, about 21 days. 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. 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.