I don't know if it would apply to you, but we had a Shetty pony, who had stifle problem and was pigeon toed. You might need help with it, but if you pull the hind leg out (which ever leg it is)(even both) and stretch it right out, and when they try to pull it back in most of the time it will click, and it will be right. I don't know if it is a muscle that's out, or somthing, but it may help you(you might need to strech their leg a few times, and it MAY or may NOT help if his is warmed up. Our Shetty was better if he wasnt, but I have no idea about your boy !)
I hope some of this helps and good luck !!
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