Brigid, there are all kinds of breeders out there.
I do agree that there can be SOME environmental factors that can affect the EXPRESSION of canine HD, but NOTHING can cause an individual who is not genetically predisposed to it, to have it.
I firmly believe this. If normal exercise and life is going to cause a pup to express HD, then truthfully, I want to know that. Because I will examine the pedigrees, and likely not use the parents again for breeding.
Puppies are not little hot house flowers. You can find so much alarming info out on the net that is written by who knows who.
My basic puppy raising formula is:
1) LOTS of TLC coupled with firm fair discipline.
2) an excellent diet. I feed raw. Raw meat is about 17% protein. Let this be your guide when looking for a food for your pup. It will be hard to find anything under 21%, but I would go NO higher than that with ANY puppy.
3) Good early positive training, and LOTS of social adventures. I have puppy out and about off my property riding in the car to GO somewhere at least 3x per week. More is better.
4) LOTS of time to just BE A DOG. Puppies need fresh air, sunshine, exercise, and lots of time to play.
Whether or not your pup will have canine HD is determined much more by what genetic combinations happened with the spermatazoa hit the ovum than anything else.