One of my orps who is at the bottom of the pecking order has been letting one of her wings droop just a little for several days now. I just inspected her and at her "shoulder" where the wing meets her body seems to pop in and out. The other wing does not do this. You can feel the joint pop back and forth and even kinda hear it. What could this be and what should I do?? I am really worried as this is my favorite hen for breeding!! Thanks!