I bought 204 chickens on special for $50. 1/3 were BR, 1/3 BO, and 1/3 were EE. They are 12 weeks old and I can't tell thier sex. This is my first flock. I thought most if not all would be roos but I am hoping to get a few hens. I believe they were overstock. I would appreciate any pointers anyone could offer to help me tell the difference between each breed's sex.