Breeders of purebred dogs usually have several goals they want to accomplish, of which canine wellbeing is one. The purpose of this article is to investigate what we ought to do given this goal. Breeders typically think that they fulfil their wellbeing-related duties by doing the best they can within their breed of choice. However, it is true of most breeders that they could produce physically and mentally healthier dogs if they switched to a healthier breed. There are a few (...) breeds that are healthier than other breeds as well as mutts; we could maximize wellbeing for the next generations by focusing all our breeding resources on those. However, in the long run such a strategy would severely deplete the canine gene pool. If we are to breed for wellbeing in the long run, we must thus weigh the benefits of selection against physical and mental problems against the benefits of genetic diversity. The optimal breeding strategy for canine wellbeing is to preserve many breeds, though not all of them. Furthermore, we ought to combine strict health programs with looser barriers between breeds. Such a policy conflicts with the goal of breed preservation, at least if we think of breeds as populations registered within kennel clubs rather than types of dogs, but not with the goal of producing good working dogs capable of performing various tasks. (shrink)