Call the Vet and discuss the issue. A clicking sound in the hips of a young dog isn't normal. It could be a growth spurt or something. Hopefully it's just an isolated thing
I suspect that the vet will want to do an xray, or a pelvic exam. It's too early to definitively check for dysplasia if that is what you are worried about.
Cut back on the walk time for now. More walks of shorter duration would be the "norm".
While a poll is a good interactive process. I would go to the Vet first off.
I supplement my dogs with Cosequine. Most would say it's gilding the lily in a young dog, but it's my lily to gild.
