II.

Physical Characteristics

Like the turkey, pheasant, quail, and other related birds, the domestic fowl is adapted for living on the ground, where it finds its natural foods, consisting chiefly of worms, insects, seeds, and greenstuff. The feet, usually four-toed except in the English breed, Dorking, are designed for scratching the earth. The large, heavy body and short wings make most breeds incapable of flying except for short distances. The crop is large and the gizzard strongly muscular. In adults of both sexes the head is decorated with wattles and a naked, fleshy crest, called the comb, which is more prominent in the male and is variously shaped in the different breeds and varieties. The typical comb is single, serrated and relatively large, either erect or drooping. A variation is the rose comb, with three rows of tubercles merging in a rearward-pointing spike. The pea comb of the Brahma has three low serrated ridges, and the leaf comb of the French Houdan has two ridges, set transversely on the head. The strawberry comb of the Malay fowl is a small, rounded, nodular protuberance set near the eyes, and the V-shaped comb of the La Flèche fowl suggests a pair of tiny horns. Plumage of various fowl ranges in color through white, gray, yellow, blue, red, brown, and black.

In size and shape the various breeds show great diversity. The 5-kg (12-lb) Brahma cock, for example, has a miniature counterpart, the Bantam, weighing about 567 g (about 20 oz). The proportions of the long-legged game fowl contrast sharply with those of the squat Cochin. The stubby tail of the latter is one extreme; another extreme is presented by the Japanese or Yokohama breed, in which the tail feathers of the cock may be as much as 2 m (6 ft) long. In general the members of one breed are alike in shape, the varieties of the breed differing in minor characteristics such as the shape of the comb and in color and markings. A group of breeds developed in a single country or geographical area is often called a class.

In habit, chickens are strictly diurnal, highly gregarious, and polygamous; cocks of the game breeds are especially noted for their courage and pugnacity with rivals. The high fecundity of the species is an important characteristic, especially because the eggs as well as the meat are prized as food (see Egg). Unless otherwise trained, female chickens lay their eggs on the ground, in tall grass or weeds. Periodically, domestic hens become broody; that is, they stop laying and show a strong desire to sit on their nests and hatch chicks. The incubation period is approximately three weeks. The chicks are precocial; that is, when hatched, they are not naked but covered with down and are immediately able to run around. Although they are able to feed themselves, newly hatched chicks can survive about a week without eating, subsisting on egg yolk that is included in the abdomen. Chickens may live as long as 15 years in captivity, depending on their breed and the quality of care they receive.