Watch the video above to learn about how hay and silage crops are harvested. Hay and silage are both fed to animals to help meet their nutritional needs. Hay is the cutting and drying of different types of grasses to be baled into bales that will be fed later to animals like cows, horses, and sheep. Silage is the cutting of crops such as corn to be stored for a longer period of time and fed after it goes through a process called fermentation.