Outside of obvious deformities and weaklings it can\'t be done. I\'ve been raising them for over 30 years now, and the
color changes as they mature are pretty much unpredictable when they are only a few weeks old. As they grow older, weed out willow legs and those with near vertical tails. The color changes will not be complete until they are adults, not only feathers but eye color as well. And it should be pretty obvious that over all type will not be apparent until they are nearly mature as well. Good luck!