
Thing is they don't know if there is a problem, woudl be sad if they found it was, and checking would have helped reduce it. That is how the problems they do have have got such a hold because of people putting their heads in the sand.
Even a cursory look at the BVA Hip scores will show that it ocurs in all breeds to a lesser or greater degree.
My own breed has a respectable record for hips, but it is the breeds policy that all breeding stock arte scored, and with over 20 scored a year the figures are pretty representative (plenty are scored that aren't bred from) as only around 120 pups registered annnually.
Interestingsly the odd high score (in the dysplastic range if comparing with OFA) are animals that are not unsound.