I have 2 barred rocks and 2 red sex links. All 4 are almost 16 weeks old. The 2 sex links and 1 of the barred rocks look the same, maturity wise, in the growth of the combs and wattles. The other rock's comb and wattles are visible but not growing at all. She is otherwise in great shape. She is as big as her sisters. She shows no signs of being ill. Just no development of the comb/wattles. What gives?
I'd say it's just individual differences. She'll likely catch up in comb and wattle development when she gets close to her laying time.
I had one bird in my original flock that developed in body with the rest but didn't develop her comb and wattles as quickly as the others. She didn't start laying until she was around 8 months old. She turned out to be the largest bird in my flock.
