I've never personally had any trouble, I've had some trouble with frozen thawed though. One of my first snakes all I could get when I first got her was mice, and she stayed on mice for awhile. I got some more snakes and started ordering rats online. now everyone eats them but she won't touch a frozen thawed one, only live, pain in the butt because around here live is over twice as expensive as frozen, also I need to make a trip to get a live rat just for her.