Okay..I am changing from a feed that I love, but just to expensive and need some help. The diet my horse has been on for the last 2 years has been 1 pound of rice bran and 1 pound of organic grain at each meal. I am thinking of Nutrena Safechoice...I would still like to keep some rice bran in his diet but how much Safechoice would I feed a 1200 pound horse in very light work. A fairly easy keeper but not an air fern...