Why are some eggs white and others brown?

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 White eggs come from white chickens and brown eggs come from brown-ish chickens. 
What about a off-white brownish yellow chicken , what color of eggs she will lay??
Here’s the answer I found:
look at their earlobes. This is true stuff. The pigments in the outer layer of the eggshell will always approximate the color of the earlobe of the chicken that laid the egg.
A natural follow-up question would be “Is one color of egg healthier than the other? According to the Egg Nutrition Center in Washington, D.C., the answer is a pretty firm no. The color of the shell has nothing to do with egg quality, nutritional value or flavor.