I would make sure that the leg is broken. If the skin is broken, there is more chance of bone infection. Is the chick holding the leg up and still getting around? Chick chairs can sometimes be good, where you can set them in front of food and water and let them heal. They can be taken out frequently to move around and sleep. Here is a link for pictures of homemade chairs and slings: https://www.backyardchickens.com/threads/versions-of-chick-chairs-please.1166308/