I am in the process of switching my snakes to rats now, All switched over without a problem with the excepton of my female Florida King. To get her to eat a rat pup I let her kill a mouse and before she finished eating it I put a rat pup in with her and while in her "feeding frenzy" she promptly kill the pup and ate it. Problem will be getting her to just take the pup with out having to have her prekill a mouse. I also rolled the pup in the mice litter (I breed my own food so easy to do, you may be able to get some from your local pet store). Try the bait and switch. My female has always been a picky eater so it may work for you.
Good Luck,
Miller
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1.1 Florida King ('02 Pit & '00 Pearl)
1.1 Eastern Kings (2004 Orca & Sugar Pie)
1.0 Black Milksnake (2005 Bubba)
1.0 Chow Chow (2003 Papi)
0.2 Cats (Stella and Shug)