Well said, Becky. And two major reasons I won't do rats as well. Also, since I have two (three in spring) corn snakes who will never have to eat rats, it's so much easier to just keep everyone on mice. If someday Nagini converts to FT, then I would consider switching her to rats. But I do not want to bring in other rats from multiple sources that might affect my three pets.
Of course, for me there is also the emotional aspect...even though I have no problem seeing the line between pet and prey.I just love rats.