Just thought I’d head this question off at the pass: what about eggshell color? What determines that? The answer: the breed of the hen. Different types of chickens lay eggs of different colors. I know there are a lot of folks out the under the impression that a brown shell is somehow indicative of a “less processed” egg, but that isn’t so. Brown eggs can come from a commercial egg farm just as easily as white ones (and many do).
Contrary to popular myth, chicken eggshells are never, ever bleached. The reason for this is quite simple: eggshells are porous. The most an egg processor will do to an eggshell is apply a thin layer of oil or wax to replace the natural mucous layer that comes off when the egg is washed. The layer helps keep out contaminants and extend the egg’s life.
One last thing about eggshell color: it’s possible to predict the color of the egg a hen will lay based on the color of folds of skin on the hen’s face — the so-called “earlobe.” Chickens with white earlobes tend to produce eggs with white shells while chickens with red, brown or blue earlobes tend to produce eggs with brown shells.