Caring for a rotating community of dogs is easier with positive training methods.
My wife and I are in a fairly unique situation in that we dogsit for charity. People leave their dogs with us while they travel, we tell them to pay us what they think it's worth (some people can't afford much, if anything; others are very generous because they know we spoil their dogs as much as, if not more than they do), and we donate the money to local rescues.
We just became a 501C3 business and carry insurance. We both have full time jobs, but when we're home, the dogs have the run of the house and a large fenced yard. We don't crate dogs while we're away unless the owners request it or if the dog is somehow destructive or aggressive. We insist that the dogs that stay with us be up to date on all vaccinations, be spayed or neutered, and be microchipped.
My wife and I are proponents of positive reinforcement training, and our situation gives us a unique opportunity to practice and observe the results on a daily basis. One of the first questions people ask is "do you have to break up a lot of fights?" The answer is no. We've kept dogs of all shapes, sizes, and dispositions, and there's seldom more than a brief snark and deferral.
We've found that when dogs are observed well, there is very little friction between them. Shy dogs gain confidence and end up playing with others, as do "overly assertive" dogs who previously would provoke others into fights. We currently have a foster dog (found by our vet tech, but nobody wanted to keep because she "didn't get along well with other dogs") and some long term visitors that we're keeping until their owners get back on their feet (situations where the owners would likely have had to surrender their dogs to a shelter). These long term dogs seem to lend a stability to the group. Oh, and we also have three cats (who have an "escape hatch" into the basement) and all the creatures are still happily cohabiting.
Many dogs do go back to their old habits once they go home and get back to their routine, but some owners actually appreciate and carry on the positive training after they leave. We're just happy to know the dogs are overjoyed when they return. Most owners say that as soon as they turn on to our street, the dogs start getting excited. Please check out our facebook page for pictures of our visitors and updates on local animal welfare news: https://www.facebook.com/LifeInAMuttshell