Sue_charp, Thank you! 4 quarts is a gallon. If you were to feed you’re horse 4 quarts in the morning and 4 quarts at night, along with good grass mix hay, you’re horse will gain weight. If you’re horse needs to be wormed I would worm it with Zamectrin Gold, it is very effective. The feed that is really good for the horses digestive system is Total feeds.