I think I might be figuring out the blue, that is what I was thinking.Works the same as any other variety with blue involved, you'd get 50% "black" in this case Mille Fleur, and 50% "blue" in this case Blue Mille Fleur. If you went Blue Mille Fleur to Blue Mille Fleur you would get 50% "blue", 25% "black" and 25% "splash" and of course the "splash" to "black would give you 100% "blue".
This applies to Blue Red, Lemon Blue, Silver Blue, Blue Wheaton, Blue Crele and any other "Blue" with the exception of Self Blue which is genetically speaking Lavendar and works differently.
Another question, though, I have a chocolate hen, has anyone crossed chocolate with mille and what would happen with that? Thanks very much for your answers.