Sadly, most breeders of designer crosses tend to be less than reputable. The Good Dog website might be a place to start. Good Dog: Find the Dog of Your Dreams from Good Breeders and Shelters It's not perfect, but they at least have minimum health testing standard to be listed on the website. You still need to do some homework, though. Cavalier King Charles Spaniels have a serious hear issue that is pretty much everywhere in the breed, so making sure that anyone breeding from then needs to be doing cardiac testing is a must. If someone says it's not in their dogs' lines, they are someone to avoid. Poodles also have some issues.