I'd say just make sure the rat is quite small, pup or other unweaned size, since your snake is used to dealing with a quite small prey item. You don't want to overwhelm it's hunting instincts or digestion with a sudden switch to a much larger prey item. Best of luck. We were able to switch a few of ours over to rats but some of them just won't look at a rat but snarf down mice like crazy. Also remember that bp's grow just fine on mice, at some point multiple mice so they don't have to switch to rats really.