Yes, you just pour corn oil on top of the feed. I would start with 1/4 cup at a time and then increase slowly. Some horses don't like either the taste of it or the consistancy when corn oil is added. Others do just fine, or love it. I would stay away from the rice, either boiled or raw. Rice is used to stop constipation (Not necessairly in horses) and can bind them up. I would worry about the risk of colic. Rice bran is totally different. You can buy that in powder or pellets. (I prefer the pellets) It is high in fat and can put weight on them. They come in 50# bags at the feed store.