When you talk to breeders about their puppies, there are a few warning signs that you may be dealing with a disreputable, unethical, or irresponsible breeder:
The "breeder" lacks knowledge about the breed and the Breed Standard
The "breeder" shows ignorance or denial of genetic defects in the breed.
The "breeder" has no involvement in dog sports
The "breeder" doesn't let you observe the puppies or adults. (Since homeowners insurance and local laws vary greatly, a refusal to let you visit the kennels may not, in and of itself, be a bad sign. You should ask for and receive a satisfactory explanation.)
The "breeder" doesn't ask any questions about you, your family, lifestyle or accommodations for a dog.
The "breeder" has no documentation of health testing and cannot provide a pedigree.
The puppies are not social or look sickly.
How to read those ads. A few more things to look out for.
"Champion lines" - look instead for Champion sired or Champion parents. "Champion Lines" means there is one dog somewhere in that puppy's family that was a champion - it says nothing about the quality of the parents at all. Anyone can buy a puppy from a champion, but it does not mean that they have any other interest in the breed but to bank on the name and make money. The puppy may have been sold as a pet and an unethical person did not have the dog spayed/neutered and is still breeding puppies. Having a Champion in a pedigree is like having a billionaire relative. It doesn't mean that you are rich unless each generation from that relative has passed down the money.
"AKC Registration" or "AKC Papers" - So what? AKC registration does not guarantee quality. AKC papers are much like the title of a car; papers are issued to the junked Chevy on blocks in your yard just as easily as they are on a brand new, shiny Jaguar. AKC does not control breeding, approve litters, or guarantee temperaments. Unfortunately, in the hands of some unethical breeders, it doesn't even guarantee that the dog is purebred. AKC Registration is automatic if you buy from a reputable breeder - they will provide all necessary paperwork when you buy a puppy. It is not a selling point, and shouldn't be treated as one.
Be wary of other "registrations," as well. There are several groups that are registering dogs, even mixed breeds, for a fee.This registration means nothing, and is of no value to you. Not that AKC papers really mean much, either.
"Extra-Big", "Extra-Small" - breeders trying for extremes are rarely raising healthy dogs, and any ad that has to stress the size and weight of the dog to sell the puppies is suspect. Usually, these dogs are outside of the breed's norm and are subject to their own medical problems due to excessive size or lack of it.
"Rare" - Why? Are there too many defects for the animal to be bred? What kind of problems does this "rare" color or size entail? Medical? Behavioral? Shop with care.
"See Both Parents" - This is not usually a good thing. Rarely will a good breeder have the luck to own both dogs for the perfect litter. If you can see both parents, it may mean that the person had two dogs in the backyard and didn't supervise them carefully enough, resulting in puppies, or that they bred to a dog of convenience they already owned.
There are some good and very reasonable reasons to have both parents on site. However, you need to ask the right questions and understand why this is true. If the breeder doesn't have an answer, or the answer is something like, "Well, they were just such cute dogs . . ." or "We bought another dog so we could have puppies," you need to evaluate whether this breeder is doing the right thing. They might be, they might not. It's up to you to ask.
"Must go now!" - Why? Are they too big to be cute anymore? Need more money? Is there a problem? Usually because there are more on the way. Be very wary of this one.