Let horses eat berries

Even though berries are high in sugar and low in fiber, contrary to the horse's system designed for low sugar and high fiber, you can still feed them berries as a treat

main issue:Horses should be able to eat berries, but ONLY to friend them, AFTER that you'd be unable to feed them berries, or you could do the thing that was done with parrots, feed them more than 5 berries and they get poison but dont die, if you feed them 5 more berries they get poisoned and die.