We have a rooster we got as an adult so we don't know his age, but he seems to have gone almost completely blind suddenly. He seemed very listless for a few day so we treated him with anti-bs. Now he's moving around his pen but it's real obvious he can't see anythign smaller than the coop or their large feeder. When I throw treats out he gets really excited and runs around trying to see them, but can't. The only way for him to focus on a treat is to find a hen by sound and peck around her head end and he's not always choosing the right end. We are giving him time to see if he improves, but would sure like to know what could have caused this. Old age? Stroke? A disease?