Okay, so when I got my chicks, I tried to make sure they were all hens. But I have one that is growing a comb and all that way before the others. I got the black ones as a mystery breed. They are almost 7 weeks old, but not quite. I have red sex links, CornishXRocks, and the black ones. The black ones were a bit hard to sex, but I was pretty sure I had all female. I think someone switched one of mine with one of my m-i-l's which was a boy. But she had two die, so I can't say for sure. They're still in the brooder, til the weather stabilizes a bit.