They can not be compared simply because dogs have completely different needs than ball pythons. A puppy mill is abusive to dogs mentally and physically even if they are kept clean because dogs have so many more needs that need to be met other than water and a clean cage. Where as ball pythons need just exactly that, a clean, dark, small space with fresh water. These conditions are what actually keep these animals stress free and healthy. So a rack type setup doesn't only meet their needs but it is actually what works best for ball pythons and I say this with experience in anything from a rack with small tubs all the way to a 8' vision cage. Ball pythons just prefer small dark hiding places. The only time they come out from hiding in a large cage is because they are looking for food, to mate or because some other factor is stressing them and they are trying to escape. In small tubs they are in a small secure hiding spot that they would actually be looking for if they are in a larger area. They actually want to be in their tubs, all 30+ of mine will go straight for it as soon as they smell it, they actually like their small tubs because it makes them feel secure. Ball pythons don't need or want large space, socialization or human affection. Dogs pretty much need the opposite so what is inadequate living conditions for a dog can be the perfect living conditions for a ball python.