About the egg colors: as far as I know all external eggshell pigmentation if present (i.e. spots, streaks, etc) comes from internal glands in the hen, regardless of species. My hens usually lay white eggs to start with and later eggs in the clutch are bigger and have pink spots that turn purple after about 3 days and go brown after about 2 weeks. The white ones stay white.
Just a random note, open to suggestions so I'm just throwing it out there: I have a white hen who lays eggs whose spots have been scratched clean off in a line from tip to base, about a centimeter wide; I thought she had an obstruction in her oviduct but her daughters produce the same. It looks for all the world like someone's scratched a line of pigment off the eggshell. They hatch fine, and this hen and her daughters lay fine; but maybe there's a genetic malformation causing a misplaced something in there...
Oh and about chook eggs, I've had some hens lay purple-spotted pink or rose-color eggs, or even white-spotted dusky mauve. Very pretty.