Sorry about your chicken. These things do happen and they can injure themselves more by thrashing around. Sometimes there can be nerve damage, but she may regain some usage. I would keep her very close to water and food, perhaps in a crate or cage near the other chickens for company. Vitamins including vitamin E and B vitamins for a couple of weeks could possibly help. I had a similar accident when I found one hanging from the handle of a waterer, but found her very quickly. I hope that she gets better, but chickens can get around with some disability.
