I have no knowledge concerning your question. At our Petsmart in Sacramento they sell animal products; it's a store; not a place where dogs go to play. Dogs are allowed inside the store to 'shop' with their person, but the dogs must be on a leash, contained, etc.
I have a Chihuahua mix and a pit/boxer mix in my home. They love to play together, play tug together, and cuddle together. I think it's more about the individual dogs than about their size.
