My brother was playing with one of my roosters and he accidentally shut the roosters head into the glass door. It's a very heavy glass door and the only thing I see is the roosters eye is sunken into the socket. It was draining for awhile with very little blood and the other eye is fine. The sunken in eye is closed now and he's silent and hes just standing there. He's the most aggressive of my roosters and he usually tries to bite or run if someone messes with him. I put him in a dog cage alone for now with food and water. I'm not sure if he is dying or just in a lot of pain. I know chickens know how to hide it well. His skull could be crushed for all I know. Please could someone help me with some advice to help ease the pain or help him get better?