flax seeds, barley, oats, and some other grains are fine for them and commonly found in supplements. Instant oats are not ok to give. Your best bet is to look for grain mixes commonly given to horses that do not contain corn or contain a minimal amount. I get rolled oats, rolled barley, flax seeds and sometimes wheat germ for a supplement mix for my chin. Keep in mind that anything added onto their normal diet needs to be given in moderation.