The problem is that she scores about a 1 to a 1.5 on the body score index. She is currently getting the best quality coastal hay I have been able to find. She and her colt are splitting a 75 pound bale throughout the day. I give them the whole bale in the morning and they eat on it throughout the day and night. By the time I throw them the next bale in the morning they are just cleaning up the scraps from the last bale.
I have never had to put this much weight on a horse before. I was wondering what type of grain/supplements you would recommend and in what quantities.