May or may not be applicable...
I've crossed my Black Australorp roo with my white leghorn hen just for kicks and giggles.
So far, out of 10 offspring...
2 cockrels- both solid white with yellow legs
8 pullets- white with black spots and green/slate legs
Seem to have better disposition than the leghorn so far... and a little better body size as well. Hoping they are just as prolific as the leghorn hen- I don't think she's missed a day laying since she started 4 months ago