The color of a horse has little to do with its soundness or performance capabilities. In the wild, natural selection saw to it that most horses were brown or some variation thereof. This allowed the horses to better blend in with their surroundings and escape the notice of predators. That's why we have more blacks, bays, and chestnuts. However, some people want a horse of a different color, and selective breeding has become big business and produced some flashy-colored horses, especially in the United States.