Maybe if you posted pictures, we could figure something out. Splay leg or slipped tendon, these can be fixed with little splints for "physical therapy."
If they won't eat, though...Some of my new chicks have gone the first few days without eating, no problem. You can try "pecking" at food with a finger to try to teach them. But if they just won't learn, even after a few days and you trying to teach them,
brownchickenfarm is probably right; it would be mean to let them suffer. Baby birds can survive a lot, but not without eating.
