They just do. Different breeds lay different-colored eggs. Eggs come in many different colors - light brown, deep chocolate brown, WHITE, off-white, pinkish and even green and blue! Some also lay speckled eggs. 

A COUPLE of key facts:

• An individual bird's eggs will remain BASICALLY the same color all the time.
• There can be variation in the shade of egg colors amongst individuals within a breed, but not the base color (brown, white, blue etc.).
• One way to tell what color egg a chicken will lay is to look at her earlobe! A hen with a white earlobe will always lay white eggs, whereas hens with red earlobes can lay brown, blue or green eggs. 
• Araucana and Ameraucana breeds, also known as the "Easter Egg CHICKENS", famously lay VARYING shades of green and blue eggs.

They just do. Different breeds lay different-colored eggs. Eggs come in many different colors - light brown, deep chocolate brown, white, off-white, pinkish and even green and blue! Some also lay speckled eggs. 

A couple of key facts: