The chicken, Gallus gallus domesticus, is the domesticated form of the red junglefowl of Southeast Asia, tamed about 8,000 years ago and now one of the commonest domestic animals anywhere, with a world population of more than 26 billion. It is kept chiefly for meat and eggs: a hen bred for laying can produce over 300 eggs a year, where its wild forebears laid about a dozen in the breeding season. A fertile egg hatches after about 21 days of incubation, the chick breaking out of the shell with its egg tooth. Many cultures hold the chicken sacred, and roosters have been used for divination, a practice called alectryomancy. Eggs, chicken eggs above all, carry a long lore of their own. Divination by eggs, or oomancy, was common in ancient Greece and Rome, where the shapes made by egg white dropped into hot water were read; later, a raw egg rubbed on a pregnant woman’s belly and cracked into a saucer was read for the coming birth, and girls in Salem Village read omens from an egg in a glass. In Hoodoo, an egg placed in a murder victim’s hand in the coffin is believed to make the killer give themselves up to the police within three days, and eggs passed over the sick are used to treat them.