My rooster is about 2 years old and usually healthy with a very loud crow. A few days ago I thought it sounded like he was losing his voice, and it continues until he sounds very muted in everything he does. Then last night I noticed his comb was starting to turn blackish. I've been raising chickens four years and never seen anything like this. Please help! Is it contagious to my hens or other birds? (Ducks, guinea, goose) TIA