Why are some chicken have browen eggs?

The color of a chicken's eggs is determined by the breed of the chicken, specifically by the genes that control the pigment in the shell.

Here's the breakdown:

* Brown eggs: These are laid by chickens with a specific gene that produces a pigment called protoporphyrin. This pigment is deposited in the shell as the egg forms.

* White eggs: Chickens without this gene produce eggs with white shells.

Fun Fact: The color of the yolk (the inside) has nothing to do with the shell color. It's influenced by the chicken's diet, particularly the amount of carotenoids they eat.

So, to summarize: Brown eggs are laid by chickens that have a specific gene that produces a brown pigment. This doesn't affect the egg's nutritional value; it's simply a difference in genetics.