Hi there, either of those roosters over the barred rock hens will create black sex links. However, neither a RIR rooster or a BCM rooster over a RIR hen or a BCM hen will create sex links, so only the eggs from the barred rocks will be sex links. From the BCM and RIR hens you will get either purebreds or general mutts that lay dark eggs depending on which rooster fathers each chick. If your BCM rooster has feathered legs, you will be able to tell which chicks are his because they should all have some leg feathers. The BCM rooster will pass on his dark egg traits so if he fertilizes eggs from the RIR hens the resulting offspring will lay darker eggs than a purebred RIR would, but lighter than a BCM. Hope this helps!