Hi I have a 15 year old paint/belgian draft cross. I'm trying to figure out what to feed him. Currently he is on a half cup (yes 1/2 cup) of oats twice a day, and msm and is fat!! He has had potassium issues in the past (not hypp, been tested), so that's why his previous owner put him on an oat diet. I think the oats are making him fat. He eats a good quality grass hay at free choice, and is worked 4 times a week, and does dressage, he is also out at least a half day, everyday (on a dry lot with hay). He has also had some other weird stuff, like last year he was peeing a lot and didn't shed well, so I had him tested for insulin resistance, which came back fine, but he was anemic?? So then I had his kidney's tested, because as a nurse I know anemia in people can be caused by kidney problems, that test was fine as well. I would like to completely take him off the oats. Do you guys have any opinions? Will he get enough vitamins and everything from his hay? I've considered putting him on the smart pak easy keeper vitamin supplement, to ensure he is getting everything, has anyone tried it?