There is a large fat gland in the tail of the duck, called the caudal fat gland. Its chest can also secrete a kind of "powder"-shaped keratin flakes containing fat. Usually, it often pecks and rubs the feathers with the fat secreted by the tail fat gland and the "pink" keratin flakes secreted by the chest hair, so that the feathers will not get wet when it enters the water. At the same time, its feathers are very light, so the entire body can be lifted up by the water and float on the water. Also, geese and waterfowl are the same as ducks. Although chickens also have fat, the amount is very small, so they cannot float in water.
