Help!!! Rooster stopped crowing and mating
Offer him some soft scrambled egg, low salt canned tuna, or good dry cat food for extra protein, and twice a week give him some probiotics or a small amount of buttermilk in his food. A vitamin supplement in the water would also be good. Internal illnesses such as a heart problem can show up at this age, and that could be responsible for the darkened comb. Just watch him, keep an eye on his poops, and feel of his keel or breast bone often to make sure he is not losing weight.