The color of eggs comes exclusively from the pigment in the outer layer of the shell and may range from an almost pure white to a deep brown, with many shades in between. The only determinant of egg color is the breed of the chicken. . . .

A simple test to determine the color of a hen’s eggs is to look at her earlobes. If the earlobes are white, the hen will lay white eggs. If the earlobes are red, she will produce brown eggs.

—David Feldman, from Why Do Clocks Run Clockwise? and other Imponderables, 1988.