Hip displasia. Something I never tho't of in walkers. Not in walker country altho I was looking at a 4 yr old on utube, possibly to purchase. He was hard pushed into big lick. His stifles were wobbling in and out. Had I bo't him he'd have been let down but those stifles were the deal breaker. I didn't know if that occurred only with the big stride or whether it would be permanent. Any input? A friend bo't a 15 yr old ex show mare and her hocks were sore. She still wanted to go and had no idea how to wind down and relax on the trails.