referring to species whose newly hatched chicks are at the high end of a spectrum of physiological development; eyes open, some motor skills (walking and swimming), significant covering of natal down and at least partly able to thermoregulate, some motor skills (walking and swimming), only partly dependent on parents for care, quick departure from the nest (nidifugous), and some ability to acquire food; includes geese, ducks, swans, shorebirds, and poultry; Latin praecox = early maturing