I wouldn't purchase a snake that is on ASF's. All it takes is one snake to be stubburn and not swap to rats and you could be stuck spending a lot of money or breeding another type of rodent forever. We got our first rat colony going pretty easy and our second one is all home grown! In the last month we had to go to the pet store once to pick up mice for one of our girls who doesn't want to eat anything but mice. We don't really mind as we are breeding some mice for the purpose of the hoppers baby snakes tend to prefer. Once you get rats going they are easy.