...how was she able to kill 2-3 before eating one?
If you put multiple live rodents in with her at the same time then it is a normal, and I assume self defense, behavior for the snake to kill more then one if not all of them before starting to eat. I have very often dealt with snakes that I had to feed live rodents to either as hatchlings or as newly wc specimens and most of my animals if you put more then one rodent in at the same time would do what you are describing. It also then becomes a trick sometimes to get them to eat any more then the last one they kill since the others are, by the time the snake gets back to them, dead carcasses.
If she is killing them and then ignoring them for awhile after which you give her more live ones then I would suggest only giving her one and waiting her out. If by the next day she still has not eaten it then I'd give her a fresh one but feed it to her in a much smaller container so she is in constant contact with it.
Either way I don't know of any real reason to offer her a second if she is not eating the first.
If I am completely misunderstanding what you meant then please let me know lol.
Sean.