FILLY FEED is a type of feed that is specifically designed for young horses, or fillies. It typically consists of HAY and OATS, which are both common ingredients in horse feed. HAY is a dried grass that is high in fiber and provides essential nutrients for horses, while OATS are a cereal grain that is high in carbohydrates and provides energy. Together, HAY and OATS make up a balanced diet for fillies, providing them with the necessary nutrients to grow and develop.