While commercial horse feeds can provide essential nutrients, mimicking a horse's natural diet is often the healthiest option. Horses are herbivores designed to graze on forages such as grasses and hay, which provide essential fiber, vitamins, and minerals. Incorporating high-quality forage into your horse's diet should be the foundation of their nutrition. Work with your vet to find out if there are certain micronutrients that your horse needs added to their diet.