The domesticated rat(or pet rat) is a native of North America. The big sewer rats are not. The cold of Alabama will not harm them. A lady in Denver raises them in an unheated breeding building for the pet trade. Predation might be a different story. They are not underground dwelers like the larger rats. So they will seek a building in which to live. More than likely it would be the home that turned them out. They will go wild faster than you think. I think they have a lot more instinct left than people realize. Still I have to agree with you that it is terriably inhumane to do what they did.