Why do eggs in supermarkets come only in white and brown shells?

Brown versus white eggs is a debate that has been around for decades, with a lot of people believing that brown eggs are more healthy or more “natural.” In fact, the colour of an eggshell has little to do with what’s inside. But nature has a much more colourful story to tell. Chickens generally lay white or brown eggs but around the world birds produce eggs in astonishing shades of blue, turquoise, olive green, pink, cream, chocolate brown and even eggs spattered with elaborate speckles, streaks and blotches. Some are like polished gems and others like miniature works of art. So why are chicken eggs typically white or brown? And what accounts for the spectacular palette shown by the bird kingdom?It’s all about colour in eggshell pigmentThe shell of an egg is primarily made of calcium carbonate. Calcium carbonate is naturally white, if left to its own devices.