they stink because the water they drink in turn makes them pee lots, which produces ammonia. ammonia is that foul odor you smell. a good solution is to breed African Soft Fur rats, or even gerbils. but from what i understand ASF's have MUCH bigger litters. you COULD breed regular rats and just clean lots, but that costs time and money. so i vote ASF's. there is a section on these boards about ASF's if you scroll down from the forum index