I would guess that your problem is ultimately a structural issue made worse, or noticeable, by getting heavy.  If that's the case, then I would be doubtful that supplements will help a whole lot depending on how bad he is.  I definitely wouldn't breed him to females that have the same tendency.  Whatever you try I hope it works.  Good luck!

Jessica

It's been about week now since he's been back on pasture and the popping is totally gone. He's slimmed down and looking a lot more natural as well.

I'm quite sure now that keeping him penned up and overfeeding him was the wrong thing to do for him in preparation for the show.

Certainly appreciate all the great feedback and tips from everyone!