I have an EE that lays a pinkish-brown egg, and in my older flock, I have a Barred Rock that lays a pinkish egg, too. Occasionally there is such a heavy coating on it, that it looks mauve.
All 4 of my Dominiques lay decidedly pink eggs. One has white speckles on it. Very cute. I have had a couple of mixed breed hens which were half Dominique, and the pink color was lost in the cross.
My one Buff Orp, as well as the other one that I lost to a predator, lays a regular brown egg. So it may have something to do with the line that you have, and how many brown egg genes they carry. It seems to me that the "pink" eggs are really a pale, pale brown, but the hue definately makes you think pink. I like the pink eggs. They look great in the egg basket.