A cross between a Rhode Island Red male and silver factor White Rock female produces brown sex-link chicks. The chicks can be separated by sex at the time of hatching since the females are primarily red and the males are primarily white. That is one major advantage of that cross, the ability to tell from the time of hatch which are girls and which are boys. They tend to produce very good numbers of brown eggs but I think I read somewhere that they stop laying at an earlier age than other layers who aren't sex-linked. I'm not certain on that though.