Prekilled eater, FT ignorer

I have a snake which I am trying to switch over to FT. I fed her 6 prekilled rats before I ever offered FT and she took fine. Now its been two weeks of a wasted FT small rat and Im beginning to think if its the FT she doesn't like or she just dont feel like eating. Can snakes tell the difference between pre killed and FT. Im soaking the rats in hot water while they are rapped up in a ziploc so that they get warm but not wet. My other snakes took fine but she just doesn't seem to care for them. I wiggle them in her face, try to make the rats look like they are running and she acts like there's nothing even there. Any opinions?

If it's floating in hot water in a ziplock bag, it's possible that the whole body of the rat isn't getting hot enough to spur a response from your BP.
In my experience with my sometimes finnicky feeders, I have to get the body of the f/t rat to over 110 degrees to get a response. One of the ways I've had results is to use one of those heat socks that you put in the microwave to wrap around the rats whole body while you're warming it up. I've made my own using rice and an old clean sock.

i totally agree with john.heat sock is a good way.

It wasn't floating it was actually submerged and the rat felt warm to the touch. I will try the hot sock thing next time. How long do you guys let your rats thaw out for? I left mine in the fridge for about 24 hours and then soaked it in hot water for 30 or 45 min. How long can thy be unfrozen before I have to worry about bacteria becoming a problem???

If I use the hot tap water method, once the rat is completely thawed, I'll submerge it in the hottest tap water possible for 10 minutes, then I'll drain and refill with more hot water and soak for another 5 minutes or so (I might even repeat again), then paper towel off quickly and present to the critters. I think you're fine with leaving it in the fridge for 24 hrs to go from frozen to thawed....