Toucan, does Costa Rica have its own set of chicken standards. What is considered a breed varies from country to country. An easy example, in France, a Marans has feathered legs. That’s not necessary in the US of A. The differences in breeds is purely man-made.
I don’t have the expertise to...
I’m an engineer, not a biologist, but I’ll give my perspective. My opinion may have some flaws in it and I’m certain some people will disagree, but maybe it will at least contribute to the conversation.
All breeds are man-made. Someone (or a group) decides what they want in a chicken breed...