The reason people breed for pure blood, is that they can be fairly certain what traits the puppies will have, however, when you mix breeds, it's all a crap shoot, they can get genes from this and genes from that, some are recessive and some are dominant, it's not really 50-50 appearance-wise or behavior-wise. Generally breeders breed mixes because they don't have breeding rights to the dogs, and neither dog is a good example of the breed, which further complicates things. If someone doesn't have a certain breed in mind when they are looking for a dog, I always encourage them to try the local shelter; they are filled with mixed breeds, many beautiful and even housebroken. Be careful, you might end up with a "bichen terror!"
