I'm not ready to accept it myself; mostly curious. Using my own eggs, so it costs nothing.I set very round BR eggs that I helped pick out the first time, and I got 9 roos and 6 pullets. I don't believe this theory. Perhaps someone got lucky a time or two and got more pullets and started that rumor, but that'll always be the case. There's no scientific evidence to back the claim that round is more likely to hatch pullets...