My 5 Australorps started really developing when they were about 7 months old and my 5 Buff Orpingtons when they were 6 months old. It has been a month for both and while the growth is substantial I don't think they are quite done. They started laying during the last 2 weeks. Some that i thought were most developed weren't even the first to lay. The combs and wattles definitely turned a brilliant red as opposed the the kind of pink they had been when smaller.