How reliable is this in determining gender? I have three black sex links and they are all relatively the same size. However one's crest is at least double the size of the other two, and much bigger than the other chicks crests as well. His actual body is the same as all the others though. This one also just acts Roo-ish. Too early to tell? They are 2 weeks Tomorrow or Monday. Being that they are sex links, what are the odds of a mistake?