If you look at the size and shape of the white eggs you may see that it matches the size and shape of a particular hen(s) brown eggs. I can tell by size and shape which hen laid which egg even when they're the same color.
Of course, I have a flock of 15 laying hens, and the most of any individual color I have is 6. I wish they all laid large or extra large well rounded/pointed eggs with uniform shape and size, but such is not the case. I can tell which hen laid which egg in my egg basket, and when my green egger runs out of brown "paint" and lays a blue egg, I can tell by shape which one is hers. I've also had my brown eggers run out of dark brown or speckling "paint" and lay light tan or unspeckled eggs also. It happens, nothing to be worried about. Her paint shop should eventually go back to normal.
