Is he on any kind of mineral? I'd get him on something like GroStrong or something of the like. High in copper low in iron, balanced zinc/calcium ratio. The others may have other stuff to look for in mineral as well.
Wow, I don't have enough knowledge of this kind of thing to offer any help, but I am sending cyber hugs to you and your pony! Hope he gets some of those problems cleared up in the next couple months. :)
If you put on him on a senior feed it should help. You need to be careful with vitamins and minerals , it dependes where you live, and what the hay /feed is like. Try googling 'Understanding Vitamins and minerals for horses " . You may get some decent articles. Biotin supplement for his hooves. It takes A Year for a hoof to grow out. His hooves should improve, it will just be time consuming. As he gains weight his overall health etc will be improving. I would be concerned with the roaring, and have him Vet checked on that to see if it does affect his breathing . Good luck .
Ok , can I wait until he gets settled at the new barn before calling a vet? I want to see how the new atmosphere and feed, turnout etc is helping him instead of making two vet appointments (twice as expensive *yikes*) Posted via Mobile Device