I don't see a list of things in your CH which you have tried for him,except beet pulp.So I'll ask if you have tried soy hull pellets? They are popular with many horses.They do need to be dampened,in my opinion,just to be sure to avoid choke.But just dampened and stirred,is all. And it takes only a minute or so before feeding. They are a favourite with cattle people so may be found where cattle farmers buy their feed.