One of my roosters has started marching rather like a Nazi soldier, sticking one leg out stiffly and straight in front of him. (It is actually kind of amusing except that I keep thinking he MUST be lame.) I have checked him thoroughly and cannot find any evidence of damage or an injury on him. Foot and leg appear to move completely fine when I manipulate it. There isn't any noticeable heat present. He doesn't appear to have bumblefoot (I have become somewhat of an expert on that particular ailment!) Is there something else I should be looking for?