We followed our breeders advice regarding diet and exercise, in fact she was fed a product called Be-NatuRal at their request, her weight has always been excellent, she was never excessively exercised as a young pup or even now for that matter and we have no stairs.
Nutrition and environment do play a part in the development of HD, however the HD gene needs to be present to develop.
Our breeders reaction has totally stumped us, as said before they have always been really nice, however when we told them about this their attitude changed. We don't know why, I'm assuming they may have had other litter syblings come back with HD as well, but I am only speculating, unfortunately I can't confirm that.
This whole experience has really knocked us for sevens, we have lost faith in registered dod breeders. I know not every breeder is the same and there are some truly wonder people doing the right thing by the breed, but our trust has been lost.