It's natural to feed live?
Well as ohh_kristina said. it's not natural to keep them in a cage. Are you going to let her/him go because of it? Since you are the snakes caregiver keeper owner whatever you want to call yourself it is up to you to provide a safe enclosure, with safe food! It only takes a milisecond for a rat to take a BP's eye out. And I'm sorry I don't think your that quick.
Neptune, Zion, Enigma,