I apologize if I am repeating something that must have been repeatedly posted before... For a horse on 24/7 pasture/hay with a couple of handfuls of senior feed a day, what do you all suggest for a supplement? The hay now is grass hay, don't know the details of its nutritional content--he gets a flake or two of alfalfa when he comes in to eat once a day. Even though he is an 11 yr. Old (?) Thoroughbred he is an easy keeper (way unlike my last TB, who was skinny and would never finish his grain), working lightly 3 - 4 times a week. He seems to be a perfect weight for the winter just now, very slightly leaning to the plump side. But I want to be sure he is getting all the nutrition he needs. Any suggestions?