I posted about my two young ones a bit ago and got mixed response (on gender), thought I'd ask now. The chicken in question is about 13 weeks, a BO/Ameraucana mix. Her comb got red before her sister's (BO/Jersey Giant), but isn't particularly big. I think it's a pea comb but I'm not sure. Her behavior doesn't seem particularly rooster-ish, though the two of them sometimes have squabbles where they sort of "leap" up at each other. Also one or the other will occasionally jump from one surface to another and accidentally land on top of the other. I am no chicken sexing expert but have always been worried about the comb redness. She is also not as docile as the other, from time to time I will reach for her and she pecks me, not hard though they're still so young. She's smalled in height and width to her sister, I figured they'd both be quite fluffy so I'm worried that's she's slimmer. But the fact that she seems vocally less mature than the other is somewhat comforting. At the moment the BO/JG makes awkward hoarse bwacks and the BO/Ameraucana peeps and bwacks. I have had a rooster before in a batch of chicks and I remember we were able to tell fairly quickly he was a he. Though he was a Speckled Sussex and they get quite fancy looking. I know it's harder to sex Ameraucanas.