those should breed true so you should only get more white crested blue's and nothing else
Polands but what kind/colour? - Page 2
Unless Polish have a special blue gene that no other breed of chicken has, the blue is still incompletely dominant. Black, blue, splash. If you go to any hatchery site and order these guys they give you the same info, as well as the chicken calculator. Now correct me if I'm wrong, and Polish "blue" is not the blue (incomplete dominant) gene.
i would get some white crested black pullets to add in with those 2 lol ;)
Your pair is so nice, they are white crested blue polish.