A chicken is poultry (a family of hen-like ground-dwelling birds.) They likely originated from red jungle fowls that are native to southern Asia and neighboring islands. Their anatomy and small brains indicate that they are possibly the most primitive bird. Commercially or domestically kept, chickens served as food (meat and eggs,) ornamental displays, curiosities, pets, and game or cockfighting. There are about 100 chicken breeds. A pullet is a hen less than one year old.