You'll never convince an irresponsible breeder that what they are doing is wrong. They already know it, they just don't care, as long as they are lining their pockets. So that is where you hit them, in their pockets. No one wants to pay hundreds of dollars for a dog with tons of potential health problems, so the best thing we can do as responsible dane owners is eduate as many people, the purchasing public, as possible. If the public is educated, the market for these dogs would dry up, and so the breeders profits. You'd be surprised how many people ask me if I would ever breed Merlin or Strider to let them know, so they can get a puppy. I go out of my way to be a little more patient than I normally am, and explain to them Merlin's pet quality flaws, despite his wonderful calm nature, and the fact that Strider is a dane looking mix, as well as a merle, and why they should not be bred. (I generally do not point out that neither of my boys are intact and breeding is physically impossible) I also point them in the direction of one of the breed specific rescues that have popped up in Illinois in the last three years for danes and encourage them to go that route. They may contact the next BYB they hear about, and purchase a puppy, I don't know. But I've done what I can.
Stella