I know of one breeder in the U. S. that only uses broody Yokohama hens to propagate all of his new Yokohama stock every year.
Actually a bit of black occurring in the tail of a Red Shoulder rooster is not a bad thing - gives an indication that the dark mahogany coloration is present and can be brought out in future breeding. With the Red Shoulders, you want to breed in a balanced fashion so that the males and females make up for each others shortcomings. If you breed two birds with overall good characteristics, there is a likelihood that the offspring will be over marked. So pair up dark birds with light birds and ones with good spangling with ones that have less spangling etc. That might provide for a winning breeding strategy.
