If you run your finger next to the groove where the tendon is supposed to be and can't feel it (it would feel something like a bit of string rolling around), I'd guess its where its should be. That chick may have just had a hard time hatching, or got itself into a weird position while preparing to hatch. I've had a few that seemed to be favoring one leg after hatch, and honestly, I just leave them be (unless they're struggling to get around, to the food and water) and they were running around like normal after a couple of days. I'd put it back with the other chicks and keep an eye on it. There's going to be some pecking, chicks explore the world around them with their beaks. If its not aggressive, just leave them to it. Chicks are usually less stressed when they're with their buddies, even if they're being pushed around.
Good luck!