When I introduced my chickens, I described that Johnny Cash had a black comb and wattles. In contrast, Pebbles (our other Jersey Black Giant hen) had a brilliant red comb and wattles.
Johnny Cash -- 9 months.
Recently, I've noticed that Johnny Cash's wattles and comb have started to turn red in color. And, more interestingly, one (and only one) of her wattles has become larger. Now, my husband jokingly refers to her as 'the one wattle wonder'.
Pebbles, for contrast.
This is my first flock of chickens, so I do not know much about their development. But to me, it looks like Johnny Cash is just really slow to develop the larger wattles and comb. Pebbles had a large red comb months ago. Maybe Johnny cash is just a late bloomer?