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Animal Attraction: Pet Store Pups More Likely to Have Behavior Problems

by Stacy Fox

Posted on May 15, 2013 at 5:48 AM

Dogs purchased from pet stores are more likely to have a range of behavior problems than those purchased from small, non-commercial breeders, says a new study released yesterday from researchers at Best Friends Animal Society and the University of Pennsylvania School of Veterinary Medicine

The study, conducted by a team of researchers led by Dr. Frank McMillan of Best Friends Animal Society, in collaboration with Drs. James Serpell and Deborah Duffy at the University of Pennsylvania School of Veterinary Medicine, is published in the current issue of the Journal of the American Veterinary Medical Association.

The research compares a wide array of psychological and behavioral characteristics of 413 dogs purchased from pet stores with the same characteristics of 5,657 dogs obtained from small-scale, private breeders. Most pet store puppies are sourced from high volume commercial breeding operations commonly referred to as puppy mills.

Results show that dogs obtained as puppies from pet stores showed significantly more aggression toward human family members, unfamiliar people and other dogs. For example, dogs purchased from pet stores were almost twice as likely to exhibit aggression directed toward unfamiliar dogs than dogs purchased from small non-commercial breeders.

They also a displayed greater fear of other dogs and typical events in pet dogs’ lives, had more behavior problems when left alone at home, and experienced more problems with house-soiling. Such behaviors in young adult dogs are reasons typically cited by people who surrender their pets to municipal animal shelters.

“We’ve long suspected that puppies coming from pet stores have a much higher number of behavior problems, but this investigation—the first large-scale study to specifically look at behavior problems in adult dogs bought as puppies from pet stores—offers strong scientific evidence to confirm those suspicions,” said Dr. McMillan.

“The results were so one-sided that in the wide range of behavior problems we included in our analysis, pet store dogs failed in every single case to even obtain one more favorable score than the comparison group of dogs.”

McMillan and the Best Friends-led research team note that the study did not determine the exact causes for each of the abnormally increased behavior problems in pet store dogs. It is widely accepted that a very high percentage (more than 90 percent) of puppies in pet stores are acquired from puppy mills.

A similar study Best Friends Animal Society’s McMillan, published in 2011 in collaboration with the University of Pennsylvania School of Veterinary Medicine, documented the psychological harm suffered by the breeding dogs in puppy mills.

“It is highly likely that this severe stress plays a prominent role in the increased behavior problems that have now been documented in the puppies coming out of these breeding facilities,” McMillan said.

The researchers do not recommend purchasing dogs from pet stores until the causes of the elevated number and severity of behavior problems in those animals can be identified and solved.


University of Pennsylvania School of Veterinary Medicine

Best Friends Animal Society