Many breeders have many dogs, and they all are in the house. There is one YTer that told me she has 12 in her house. And the breeder that I got Chachi from has 25. She rotate hers between the house and the garage, which is part of her house, and the yard.
Actually it's the Damned Dept of Agriculture that proposes that they be kept in separate buildings, like they're animals.
So if the place is licensed by the Department of agrculture, chances are they keep them in a separate building.