The lavenders are known for their feather fretting, unfortunately. All lavender breeders I know breed back to black to fix this problem every third breeding.
If you want to see a beautiful lavender project check out John Blehm's site Fowlstuff, he createda Silver Lavender Ameraucana and they are gorgeous. I believe it took 5 generations but don't quote me on that! Even the newly hatched chicks are beautiful.
I might have better luck in what I am trying for with a Blue and a Black Orp. then, for my project pen that I am thinking of starting up, rather than to try the Lav. Orp.