I've seen so many threads saying the comb develops at 6 weeks ish, but I've been seeing a ton of comb and wattle starting at a mere 3 weeks on, and my SLW boys at four weeks have super combs and clear wattles. Or at least, two of them do. One is still probably a boy, and the other is likely female. My EEs were the same way; I could see a difference in combs that everyone here said it was way too early to see. I look at pics of other people's older birds, and the boys don't have red features nearly as clear as mine. Is there some reason they're showing these traits so early?
Also I find the roo who gets the "dominant" role develops faster, and the other one still looks more "pullet" ish, even though the comb is still much bigger and redder than the girls. I'll try to get some pics today to show you what I mean.