My rooster was attacked by a possum (we think) while protecting the hens. This happened last week. We lost 1 bird and now the rooster no longer crows. I can not see any injuries other then the comb that was bloody after the attack. He was acting lethargic for a few days and hid in the chicken coop. I was was heartbroken at the thought of loosing him. I added Raw Apple Cider Vinegar to the water a he is drinking and will eat, but when he opens his mouth and tries to crow nothing comes out. He will shake his head like he is choking or has something caught in his throat, but I cannot see anything. I called several vets in the area (we live in farm country) none were willing to help. Is there anything I can do to help him? Will he crow again?