The most basic requirement in a horse's diet is long-stemmed forage, either in the form of grass in the grazing months or as hay when not grazing. When feeding hay, the quality is just as important as the amount. Clean, leafy hay with good color is ideal but faded, weathered hay can also be adequate as long as it is not dusty or mouldy! This is extremely important if one is feeding large round or square bales free choice as the horses tend to chew holes in the bales in search of fines and this creates a breathing mask that allows the horse to inhale all the dusts and molds that it mobilizes while eating. For this reason, allowing horses free access to large bales is not recommended. When choosing grains or supplements, making sure they are fresh and properly stored so there are no molds present is very important.