For weeks, I have been going back and forth --w/ black true Ameraucana chick.. It was my largest chick--I just knew it was a roo.. Waited a week, no color in the comb like the other two roos--might be a pullet... Waited a week, comb not growing and is only a tiny pink...still might be a pullet. waited a week, oh yea, it's a roo, still growing and much larger than the little pullets... And today, I go to feed them and let them out of their coop----well there on this chick's back were those ARROW shaped feathers, almost jumping up at me!!! SO, now I know HE is a Roo!!! These chicks are about 12 weeks old, have rose combs--so I have been REALLY struggling w/ gender..Thank you all, for your description of the key things to look for!! There will be three young roos leaving today, they will go to a good home and wait for their own flocks!!!