All of my lavs are from Bren/Deb's lines, and all of the lav chicks hatch out self blue with very muted lav and lighter lav stripes. They are all lavs. The "mutts" like your darker one are splits. They'll feather out silver partridge (gray), but when mated back with a "pure" lav or with each other, should produce some lavs. When bred back to a pure lav, the babes will all be either lav or splits carrying the lav gene. My lav/black split babes have all been a very bright black with NO white. Those splits, bred back to each other or to pure lavs will also produce some lavs. I've also gotten one (confirmed by the experts) lav out of my porcelain project, which to me stands to reason, as both parents are of lav/buff background. I recently got one lav from my black pen, but I knew the roo, a lav/black split showgirl from Bren and some of the hens were lav/black splits.