chicken

The chicken (Gallus gallus domesticus) is a domesticated fowl. As one of the most common and widespread domestic animals, and with a population of more than 24 billion in 2003, there are more chickens in the world than any other bird. Humans keep chickens primarily as a source of food, consuming both their meat and their eggs.

Conventional wisdom has held that the chicken was domesticated in India, but recent^[when?] evidence suggests that domestication of the chicken was already under way in vietnam over 10,000 years ago. From India the domesticated fowl made its way to the Persianized kingdom of Lydia in western Asia Minor, domestic fowl were imported to Greece as late as the fifth century BCE. Fowl had been known in Egypt since the 18th Dynasty, with the "bird that lays every day" having come to Egypt from the land between Syria and Shinar, Babylonia, according to the annals of Tutmose III. Domesticated fowl do not appear in the Old Testament.

The chicken is believed to have descended from both the Red and Grey varieties of Junglefowl (G. sonneratii), though hybrids of both wild types usually tend to be sterile.^{[citation needed]} Recent genetic work has revealed that the genotype for yellow skin present in the domestic fowl is not present in what is otherwise its closest kin, the Red Junglefowl. It is most likely that the yellow skin trait in domestic birds originated in the Grey Junglefowl.