Hrmm. Well, I have four laying per day, and I really only have four shades. I can match eggs up and have a batch all from the same hen. My buttons are the same way. My little bluish-green egg laying button was thrown off laying because I had to clip the sharp part of her beak off because she's nasty. I would say that they lay the same color egg, if they lay speckled eggs, she should always lay speckled eggs, if they lay blotchy ones, it should always be blotchy, etc. But, I could be wrong, this is just my limited experience with my own flock.