Animal advocates say it's up to buyers to do their homework when it comes to purchasing a puppy from a breeder.

The issue was highlighted by the seizure of 66 dogs from an alleged puppy mill in Langley, B.C., last week.

"We never thought that somebody like this who is exploiting animals for profit would be using B.C. as a safe haven, but it seems like that is what they're doing," said Geoff Urton, senior manager of stakeholder relations at the BC SPCA.

Advocates say more needs to be done to prevent people from establishing puppy mills.

But for now, the onus is on individuals to check the breeder's practices before buying.

Here are few things to watch out for when you're looking for a dog breeder.

1. Prevents you from seeing where the animals live

Reputable breeders often have a waiting list of people wanting to buy a puppy from them, said Kathy Powelson, executive director of Paws for Hope. (CBC)

Reputable breeders will show potential buyers where the dogs live and play, said Kathy Powelson, executive director of Paws for Hope. She also suggests taking note of the health of the puppies' mother and father.

"Their health is going to indicate the health of your pets as well."

2. Sells animals to the pet store

"No reputable breeder would sell to a pet store. If you're buying a pet from a pet store, you're buying it from a bad breeder," said Powelson.

The same rule applies for breeders on Kijiji or Craigslist who allow people to "select and purchase [puppies] online like you would a pair of running shoes."

3. Sells multiple types or breeds of designer dogs

A reputable breeder will generally stick to one or at the most, two different kinds of breeds said Powelson.

"They really are expected to be experts about that breed — their temperament, their health, their behaviour, and their lifestyle needs." Someone who breeds many different kinds of dogs is less likely to have that level of knowledge.

4. Has multiple litters available for adoption

A good breeder will breed their own dogs once or twice a year, said Powelson. This means reputable breeders often have a waiting list of people who want to buy a puppy from.

"[Reputable breeders] are actually going to be choosy as to where those dogs go as well."

5. Does not sign contract outlining responsibilities and expectations

Breeders who care about their dogs will take responsibility of the animal for the entirety of its life, said Powelson.

"If your life changes and something happens and you're no longer able to take care of that pet, then that breeder should take that pet back," she said.