No, they are not rare. Pitbull puppies are born with blue color eyes but don't pay a premium price to breeders for blue eyes, as the blue eyes are not forever. Keep in mind, most dog breeds are born with blue eyes, but once they grow, their eye color starts to become dark. The reason for blue eyes is the low melanin production in dogs; once they grow, melanin production increases as well, which darkens the eye color.