Animal genetic resources for food and agriculture of animal genetic resources includes diversity at species, breed and within-breed level. Known are currently 8,800 different breeds of birds and mammals within 38 species used for food and agriculture. The main animal species used for food and agriculture production are cattle, sheep, goats, chickens and pigs. In the livestock world, these species are often referred to as "the big five". Some less-utilized species include the dromedary, donkey, bactrian camel, buffalo, guinea pig, horse, rabbit, yak, goose, duck, ostrich,partridge, pheasant, pigeon, and turkey. The history of animal genetic resources begins about 12,000 to 14,000 years ago. The domestication of major
Chicken breeds recognized by the American Poultry Association Chicken breeds recognized by the American Poultry Association All chicken breeds recognized by the American Poultry Association are categorized into classes. Standard-sized breeds are grouped by type or by place of origin; bantam breeds are classified according to type or physical characteristics. The large breeds are divided into six classes – American, Asiatic, Continental, English, Mediterranean, and All Other Standard Breeds – largely according to their place of origin. The American Class contains thirteen breeds which originated in Canada or the United States. All are heavy breeds, and most lay brown eggs; most are cold-hardy: These three breeds originate in