I don't mean to sound rude, but you're not at all informed when you say that not many dogs are born on the street. That is absolutely not true. I deal mostly with exactly that - dogs born on the street, in ditches, truly homeless. I used to think the same thing that you did though, that it was mostly cats that were reproducing and living outdoors. Sadly, dogs are right up there with the cats. Puppies growing up in drainage ditches, becoming feral and being "rolled over" as the locals called it, which means run over by cars, quite a common occurance, eaten by predators, attacked by other dogs, killed for fun by kids that don't know any better. As a method of dog control, I've seen first hand hungry dogs lured out to the dump, shot and left to burn with the rest of the garbage.