What a big lug he is
Your feeding hay too right?
I keep mine on free choice hay 24/7 in the winter and pasture grass in the summer. I give them a small 1lb once a day of a pellet feed, but that's mostly just to get them used to coming up every day.
They have a salt block with minerals all the time too.
I'm of the mind if the horse isn't being worked hard, hay/grass is really all they need.