I get asked, all the time, why I think that pet over population is not a problem in Washington state, which is where I send most of the dogs I save. Do I think they have better laws? Do I think they are more educated to pet over population thus being more willing to spay/neuter their pets or refrain from breeding? My answer is "no". I've done zero research to back up my theory so it is just my opinion and should be taken as a point to possibly argue. I believe the key reason you do not see the abundance of unwanted dogs and cats, in the Northwest, is the weather.
Last January, a friend in rescue south of Corpus, reached out to me and asked if I would take a momma dog and her 8 puppies, who were living under a trailer in an oil field. The temps were predicted to reach freezing, over the next few nights, and she was afraid for the dog's lives. In Wa, in January, they would be freezing on a daily basis. These puppies would have little to no chance at survival.
This past October, I drove south east of San Antonio, to a very rural community. I was helping another group try to round up over 80 dogs who had been living on a man's property. The man's home had burned down and he was living with relatives. This man had allowed his dogs to roam freely, unfixed, for years. They had been mating every year, twice a year, for who knows how long, and had gone from 5 to 20 to 40 to 80 dogs. They all lived outside the home, under sheds, broken down vehicles and in drafty barns. If this had been in the North, where you have harsh cold winters and animals left outside, freeze to death, most of these dogs would not have lived much less their tiny, vulnerable puppies.
In the south, to be a backyard breeder means you can, literally, put two dogs in your backyard, let them have at each other for a few days, and 9 weeks later you have puppies. You can then let them wander around your backyard till pups are old enough to sell. Post a "dog for $$" and you've made yourself a few bucks. In the north, there is no "backyard breeding". You'd need to actually provide shelter for the mom and babies so they don't freeze to death. That would cost money and next thing you know, your profit margins are so small it doesn't make sense to breed at all. Also, in the south, you'll often find breeders can get two litters a year out of their dogs where, in the north, they are less likely to go into heat more than once. It's because their bodies recognize that it is too cold, in the fall, to safely have pups. Once again, weather...weather..weather.
I do think that, because you can't find puppies, on the side of the road for $5 a piece, that people in the NW treasure their dogs more than people in Texas. To see the condition that some dogs are kept in and to hear people say "don't tell me what I can or can't do with my dog" highlights the fact that people, in the deep south, consider their dogs nothing more than property and not another living being to be treasured and loved. My heart broke (as did every rescuer and dog lover I know) to see the number of dogs relinquished over the holidays, just because their owners didn't want to pay the money to have them boarded. No problem, take this dog to the shelter and I'll find a new one after the holidays. There are so many to choose from.
As long as Texas continues to be the number one state in the union for euthanizing rehomable pets, my group will continue to work to find them new homes in the North.