Your description sounds like a slipped tendon. If you want to try to help it, you will have to catch it. If you don't have one, get a net with small mesh to use to catch it.I wonder where I posted my reply. Anyhow- I have not been able to get any pictures that are capable of showing what is wrong. But the baby is still managing. Keeps up somewhat with its siblings. Roosts- but not as often as they do. Im hoping as it gets bigger, it will fly up on the top roosts better. If they would realize I am not a monster and run away so far in to a pile, I would be able to get pics.
Its foot turns outward, like it broke its ankle.
You can do a search in the Emergencies forum for slipped tendon to get an idea of what you might be able to do for it.