If you have true, first generation sex links, the roosters would indeed by white and have brown saddles. But at this age, you'd recognize the roosters as HUGE, they'd be crowing loudly, walking upright, and be very, very obvious. In a flock of hens, a couple hens rise to the dominant position and take on the rooster's role in the flock. They tend to boss others, be alert for dangers, etc. It's entirely natural.