Not to be confused with a shameless "doggie factory" that exacerbates the domestic-canine-overpopulation problem, this type of disgraceful also-valuing-wealth-over-public-welfare establishment merely prints up fake "emotional-support animal" or "therapy pet" certificates, so that you can have your waggy-tailed buddy accompany you anywhere you wish, even places with a "no pets allowed except service animals" rule.
In part one of the "Wishbone" episode, "Halloween Hound", Joe doesn't need the services of a puppy diploma mill to be allowed to have Wishbone come into Oakdale Sports and Games with him, since shop-owner Travis Del Rio assures Joe that he likes dogs.