How do I find and assure the integrity of a Schnoodle breeder?

Schnauzer + Poodle = Schnoodle. We adopted Frida and Kahlo 11 and 13 years ago respectively. Since they are getting on in age just a bit, we want to find a good breeder. I have read about puppy mills getting into the act and have also read about breeders that breed Schnoodle to Schnoodle rather than Poodle to Schnauzer. The breeder we used before is no longer in business so any help would be appreciated.