He is very cute here.
He may (or may not) have epiphysitis or (worse) osteochondrosis. The former can be cured with cutting back food and weight, the latter not so much and usually leads to the horse being put down.
Hopefully NEITHER of these is the case and I look forward to photos/video that clearly shows the issue.
BTW I like his dam and the sire looks not too bad either. Hope there is no real issue.
There is something about the outside of a horse that is good for the inside of a man. ~Winston Churchill
) Dinosaur Horse Trainer