I have 6 New Hampshire Reds, they are now about 4 months old and just started molting, since they were just a few weeks old we could tell that 2 of them were roosters it's still obvious they are now, they have large combs that lay over, I would say maybe 1.5 inches long. And up until the last two weeks the other four looked like hens to me. but now I am starting to wonder. one of them has a very small comb, obviously a hen. but three of them are starting to get longer combs, not much but definitely longer than the known hen. but the comb doesn't lay over, I would say it's about 3/4 of an inch long sticking straight up. here are some photos. Here is the obvious hen. Here is one of the three that we thought were hens, what do you think? Here is one of the known roosters on the right, and one of the questionable ones to the left.