Half Paint/Half Draft eating... I know I asked a similair question.?

I havea half draft and half paint. He is about 15-16 HH.And he is really skinny. Before my mom got him, he was in a pasture with weeds. He was nice and muscled out. No he lost alot of weight. And for the people who answered my old question. We feed all four of my horses-a scoop of strategy,a scoop of normal, a cup(the one it comes with) weight builder, and two-three scoops of beat pulp, twice a day. And we give them 1/2 to a whole bale, because we have no gr. So is there anything else we can do? And what do we do about the gr thing?