Welcome Good for you for helping this poor horse... My first horse looked like this when I first got him... The vet told me: Do Not Put Weight Back On Too Fast...A horse in this condition might take a year or more to gain back his full weight...I was always told to do it slowly.... Just use good quality feed & supplements(vitamins & minerals), worming later on, don't feed too much alaphfa hay mix some in with a good grass hay & keep the ration balanced...time will do the rest... He looks