Chick is standing on its leg, but seems to not want to use it

[mogto]

Ok, so I had a very poor hatch rate (ten percent) and the ones that DID hatch did so 2 days early. I suppose that due to being two days early, they had some minor problems. That is, their toes were curled. Nothing else seemed to be awry. However, now that they are two weeks old, and in a cage outside instead of a mesh bottom cage inside, I noticed one of them can stand fully on its leg but does not seem to be able to use it that well. It's cocked out to the left a little, and he will just leave it in place while he uses the other leg, effectively making it a bird that's really good at walking in circles. The knee joint (or ankle, whatever it is) seems to be ever so slightly larger than the other leg. was it broken at one time, and I just failed to notice it? Or is it a birth defect? Or hopefully something I can train the bird to stop doing? I have a video, but cannot post it until I'm on Wi-Fi. I hope someone can get what I'm trying to say without the help of a video, though. I apologize for the wall of unorganized text, I'm posting from my cell phone.