I have only a few dozen as reference, but after my first 7 boys, I've gotten pretty good about telling the gender of my orps.
I prefer at 2-3 weeks to watch the wattle development... nothing is foolproof of course... but I've noticed that the boys so far, have a part in the fuzz; a line of skin showing through, very clearly and perhaps even a little growth.. while the girls still look very much like chicks in the face and have little to no part in the fuzz for the wattles at that age.
but that is just so far... who knows! Not to mention sometimes, the just look bigger, act like roos and even start to crow early! LOL
Look at the pic. of grown hens. Their combs are very red and large. Combs of young hens are usually a pale shell color on RIR. The boys will usually be a bit larger and a little darker shell pink color than the girls. Also as they age the comb progresses to a deep stawberry color esp at the bottom of the comb. Hope this helps Jean
) at about 4 days! He has big feet and stocky legs, he walks differently than the rest (less of a waddle, more steady). And he always has his head poked up right off the bat when I walk in the room. He has also lowered his head and given the "I'm gonna kick some butt" look. I hope I'm wrong, but these all seem like signs to me.