did you try feeding her some canned cat food? the extra protein will help her feathers, and most chickens can't resist it. Some plain yogurt mashed with some feed is usually a crowd pleaser too. She probably hasn't eaten well in a couple of days, and you need to make sure she is eating enough. How is her poop looking?
She might have suffered a twist or a blow on her leg. Is there any swelling on it? or does it seem to be stuck in a bent position, anything unusual there?
She might have suffered a twist or a blow on her leg. Is there any swelling on it? or does it seem to be stuck in a bent position, anything unusual there?