The rooster looks as expected with a dominant white bird crossed on a red bird, but the female does not. Are you sure one parent was full white leghorn? If so, the female should not have black tail feathers. Or was one parent a hybrid containing White Leghorn? I have direct offspring of Rhode Island Red x White Leghorn, and they are solid white, and their tails are different than the ones in the photos you show. Are the two birds you are showing siblings? I thought you said in a post in another thread that you could not have a rooster?