I have a kennel of Llewellin setters (Jornada Setters), the Llewellin is a strain of English setter, but registered (since 1902 with FDSB) and bred separately for 150 years. They're hunting dogs, upland bird dogs bred for performance and soundness. I ship puppies and trained setters to every state in US and Canada. We'll produce 12 to 14 litters a year and 15 to 25 puppies will be held, trained and developed then sold, or kept for entry into the breeding program. That's a little background on my kennel.
I'm a Cal Poly (SLO) graduate in Animal Science, but that was many years ago so I've spent the last several years studying genetics to help in my decision making with the kennel.
While many of us love to read the advice of a master breeder, the reality is that the vast majority of bird dogs come from backyard breeders, who make a few dollars in the spring with their bitch before hunting season or the fall field trials (if they do either), and many have websites that begin with “we are a small kennel in..” meaning two to five dogs that are thrown together for an “awesome” litter every year or so.
The breeding kennels that select and cull, and breed with outstanding sires and dams are far and few in between. And I’d say the Llewellin is a breed at the top of the list with rarely any one spending the time and money to make an improvement to this breed.
Most dog breeders worry about canine genetics, but very few worry about genetic management of their breed. This is the reason why there is a growing list of genetic disorders, and also the reason why DNA testing without a change of breeding practices will not eliminate genetic disorders in dogs. Worrying about canine genetics without also worrying about genetic management invariably does more harm than good. Convincing Llewellin setter breeders of this is as important as improving my kennel.
The point is, it is more appropriate to look at genetic diversity in a breed as the number of distinct lines, not the genetic diversity of any individual dog and with the strong selection for desirable traits by many breeding kennels,