White Jersey Giant chicks are grey, they turn white when the feather out. If your cx lives to lay, most just die but I've heard of some people having them live that long, what you will probably get is a more efficient JG and a less efficient CX. What you will probably lose is the size of the JG and the meatiness of the CX. Doesn't hurt to have a side experiment though. I have white JGs coming from SandHill, supposed to have been last week but I put down all of May and June as alterative hatch dates. I plan on putting a pullet in with my white silkies to up their size, hoping for some giant black meat chickens. I will keep the rest purebred. If it doesn't work out with the CX try to find some good heritage white cornish rocks, or delaware if your still interested in a cross.