Pardon the misspelling on my title. It won't let me change it. Lol.
Edited by Sweet Coastal - 11/15/15 at 8:05pm
I think that is probably a slipped tendon which is very hard to do anything about. The swelling is pretty common, and these chicks usually have a leg bone deformity that worsens with age. It is however worth trying to treat with splinting and giving poultry vitamins with trace minerals (something like Poultry Cell or Poultry Nutri-drench 1 ml daily orally.) Here is some reading about slipped tendon--read post #3 for more links: