I think there are two seperate issues here one is pts a health pup that is the wrong size, shape, colour, markings usually pet homes can be found for these, often at a reduced price and with restrictions or no KC reg, I know this does not completely prevent breeding, but it is less likely. The other is whether a pup that is healthy in all ways apart from its disability should be kept alive. In an ideal world there would be wonderful loving homes waiting for all these pups, unfortunately while their are people who will offer homes to these dogs, there probably just aren't enough of them. The rescue centres and breed rescues are always full of dogs. It would be a very difficult decision to make, luckily for me I have never had to make that decision. I have however come accross a few people have have ended up with more animals than they know what to do with, this effects the owners and the animals quality of life.