And I didn't mean cut his food way down - if he's a healthy weight you want him to stay that way. A lot of horses are going to have a hard time gaining muscle and getting in shape if out on pasture all the time though. We turn our horses out for 3-4 hours a day on pasture, and then feed a grass hay for the other meal(s). I am not a nutrition expert by any means, but if you do want to keep feeding a grain or something as a supplement to hay, I feed a little bit of Purina Strategy - I don't feed much, only enough to be a treat to my horses (about a cup once a day). Besides my show horse, the rest only get rode about once a week, so are pretty easy keepers.