I have a BLRW Roo that has developed a leg injury. The other day, he was barely limping. I just checked him for bumble foot, splinters and other obvious injuries, but could not see or feel any issues. Now, just a few days later, he can not hardly walk and just lets it drag behind him, and lays down with it sticking out behind him every chance he gets. I have isolated him in a pen I use to brooder older chicks in the coop before introduction to main flock. Is there anything else I may be able to check and help determine the root cause of the issue?