In “Early experience and the development of behavior” James Serpell and J.A. Jagoe show the relationship between problem behaviors in dogs and where they were raised.
Aggression was significantly more prevalent in dogs bought at a pet store, followed by:
Found – as a stray and kept.
Breeder – as in large breeder with pups raised in a kennel environment.
Lowest in dogs bred in a home environment, including by a friend and family member.
Regarding social fears, the highest rate was again in dogs acquired from a pet store, followed by:
Found and large kennel Breeder ranked about the same
Lowest again when bred in a home environment.
The authors didn’t elaborate on aggression and social fears, so we don’t know if the dogs threatened, bit, resource guarded or what. And of course, social fears can also be the root of aggressive displays, and the fact that they separated the two leads me to believe that it was timidness and nervousness they were referring to.
Can’t say that I am surprised by these findings. No pet should ever be purchased in a pet store, and I have a peeve with large kennel breeders, who have 2,3,4 or more litters going at the same time, year around. Even if the dogs and puppies live in a house, and not in a barn or outside kennels, the environment is stressful, and there isn't enough time in a day to give each pup the care she needs to turn into a well-rounded adult.
Shelter dogs having a higher rate of social fears is what I experience as well. I work(ed) with many rescue dogs, and rarely me(e)t one who is not on some level anxious or insecure. But don’t stop adopting, cause in almost all cases that can be fixed, and you end up with a wonderful companion.
The second highest aggression rate in found dogs could be explained with that they might have been ditched in the first place because they were aggressive.
That the lowest occurrences for both aggression and social fears were seen in dogs that were lovingly bred in someone’s home is food for thought, cause it, of course, includes people condescendingly trashed by many as back yard breeders.
I've never seen anything wrong with someone who has a really nice dog or two and wants to pass on the great genes, often keeping a pup for himself and finding homes for the others in their friend and relative circle, or even, arrgh, advertising it on-line. And I am so against on-line dog shopping. I really am. But there are exceptions and sometimes a lovingly raised pup can be found there. Doing the proper research are the key words here.
If I’d be shopping for a pup, I would not rule these people out. I would also not rule out breeders who have a more commercial business going, but would most certainly shop locally so I can see with my own eyes how the puppies are raised, and how their parents live.
But my heart is really with dogs looking for a second chance. I am a sucker for dogs who have social fears, cause there’s nothing more rewarding than when they overcome them and trust again.