I don't think Ralph uses the terms "sibs" to indicate that he knows there's something special or unique about them. Just that there is a chance there could be....so he designates them as a "sib" to a lesser in a platty-daddy clutch (for instance) because he doesn't want to just sell them off as normals and have whatever mystery gene they may be carrying to get lost. Whether he keeps them or sells them, he's very interested in seeing if they'll prove out to be anything special. So it makes perfect sense to me to designate them the way he does and to sell them for more money than a normal from say...an albino/het clutch.