Update: My chick that was struggling with his legs is doing better. He doesn't lay flat on his back now. I have kept him in an egg carton and I think it is helping. I tried to put him in with the other chicks but he is still pretty wobbly and it seems to draw their attention and they peck him. So, for now he is back in the bator until the morning. I will try to reintroduce him to his hatch mates again tomorrow.