I find the pink egg interesting. I have read that there are only two true egg colors. White and blue, with blue being dominant. So a bird actually only has either white or blue and that would be what you would see inside. I thought pink would be a white egg with one of the sixteen brown egg genes deposited on it to create "pink". That it goes all the way through the shell is perplexing.
I used a very fine sandpaper to find out if the pigment went through the shell since the inside of the shell was pink also. It's wierd. It's subtle and you would never think to notice it until one day you look at a group of broken shells to grind up for the garden and the interior of the shells catch your eye as you toss them in the blender. So I took a fresh egg to clean and sand to test for pink shell pigment.