Stacked hay in Romania. Hay is a generic term for grass or legumes that have been cut, dried, and stored for use as animal feed, particularly for grazing animals like cattle, horses, goats, and sheep. Hay can also be fed to pets such as guinea pigs and rabbits, though they consume much smaller quantities. Pigs may be fed hay, but they do not digest it very efficiently. Hay is fed when or where there is not enough pasture or rangeland on which to graze an animal, when grazing is unavailable due to weather - such as during the winter, or when lush pasture by itself is too rich for the health of the animal. It is also fed during times when an animal is unable to access pasture, such as when animals are kept in a stable or barn.