Do you have to do anything with beet pulp before you feed it? I'm trying to also make things as simple as possible for the BO.
You don't have to do anything to it if your horse doesn't bolt his feed. If he does gobble his food fast, then you'll want to soak it for 15 minutes or so.
You do not have to soak alfalfa pellets, as they crumble easily when the horse chews.
I personally thought some of the reactions that were posted were a little extreme, I just wanted help, not a guilt trip. He is ribby, but his coat is soft and shiney and his eyes are bright, so hopefully some changes will give him that extra umph to gain some weight.
No, he's not terribly skinny, but he's gotten worse since you got him and you said you've been trying to put weight on him. Which is why we are concerned. Giving more food without good results means you're either giving him the wrong food (too much starchy/sugary grain and not enough hay is my guess) or there's something wrong with him (bad teeth, parasites, ulcers, etc.). Since his coat is good, he has okay muscle tone (for what muscle he has left) and his feet don't look crumbly, then it's not likely that he has anything wrong with him. So, you need to look more closely as his diet.
I have been in your situation with three different horses now, similar breeding (TB or half TB). What WORKED in each situation is no grain
, more hay, alfalfa and/or beet pulp, and a fat supplement (flax or rice bran).
IME corn oil didn't work as well as flax or rice bran, but if you have it, it's worth a try.