It does sound possibly dislocated but it's impossible to say for sure. Can you get a photo of it? It may be a slipped Achilles tendon. There's some info on leg injuries and issues on this site to look through, chances are it's the same site most people here would link you to, it's pretty much got everything covered:
There's a chance she has a disease, as she's been targeted before by the sounds of it, but too early to say for sure.
As for the feather picking, I'd watch that, it can descend into cannibalism and indicates underlying presence of that trait in most cases. It's not a trait all chooks have, it's something noted to be strong in certain breeds and absent in others, though with certain husbandry methods for enough concurrent generations I'd expect you could cement that trait into any breed. Generally they say it means lack of protein, but some birds are obsessive about it and it's got nothing to do with hunger, and other birds will starve to death without even considering cannibalism.
Sometimes, in birds predisposed to cannibalism, including obsessive featherpickers or feather-eaters, all it takes to trigger a frenzy of cannibalism is for a single drop of blood to well up where a feather is ripped out. So I would consider their repeated featherplucking to be a potentially serious risk.