I'm here in missouri, the puppy mill capital of the world.
I can say for a fact that MOST of the breeders of these designer dogs in fact DO NOT health or temprament test breeding stock, and the reason for the breeding has nothing to do with trying to get the best of both worlds.
It's all about unique breeds and breed names. Since they aren't registered (unless it's with one of the mill-specific "registries"), they don't even have to start with registered breeding stock.
Since many of the mills specialize in small dogs, now they are getting on the bandwagon by crossing those breeds for designer breeds. Designed for nothing but making money. They may make up reasons for the cross, after the fact, but it really has nothing to do with why they did the cross in the first place. It's like they are all trying to be the first to come up with the most unusual cross.
There, that's MY soapbox.
vickie