When I was younger, we had several H Q RIR's that would lay a pinkish egg... The interesting part, was these eggs would actually change colors... After cooled down, you couldn't tell a difference in them from the browns-- until warmed up again..
here's about what you need to know... you have white layers, and browns. The only thing left to need is green and blue and dark browns.. pink does not exist- its more by chance.
If you take the dark browns and breed them to the blues-- you get olives.. if you take the browns and breed them...