storing eggs/white vs brown eggs

It seems that only in America do we buy our eggs from the dairy section of our grocery store that have been refrigerated. But I once visited S. America, Paris, and London (not all at the same time) and they all sold eggs right there on the shelf--- not refrigerated. I'm curious about that. Also, I noticed that they only had brown eggs, I never once saw a white egg...I already read the posts on why they're different, etc. but it's interesting that those countries prefer chickens that lay brown eggs.