I was going to post the site, but I couldn't find it at the moment, I've seen them located on one hatchery site, just don't remember the name. I did find self-blue D'uccles on one I did check out looking for the silkies.Well, if the one you have sells those, I suppose the whites could carry them. Lavender is recessive though, so just to outcross to black and then breed back could take a year, at least.