It is the little things that are different from country to country. A while ago, I noticed that eggs from free range chickens in the Netherlands are always brown, while the eggs from chickens kept in small boxes are always white. Discrimination! It is not so hard to see why it would work like that. People associate brownish with more environment friendly, non-bleached toilet paper, recycled paper, that kind of thing, while white is too clean to be friendly (same reason that recycled toilet paper isn't very soft. Good for nature can't be nice to your backside).
In Switzerland eggs from free-range chickens are white (or at least the ones we tried). May be the Swiss are too font of clean and white to have a prejudice like this kick in and discriminate against brown eggs.