You want to do like others have said in there posting.
The method is called scenting.

I have an albino that is a mouse destroyer and it gets expensive considering her size and how many big mice it takes to feed her in the aspect that one medium rat can equal 7-8 mice in equal weight depending on your feeder supply of course...

What I do is save all the nasty mouse bedding in a five gallon bucket. I then drop the rats that I feed her in there a day ahead of time with scratch feed and the next night I have rats that smell like mice and she eats every time. Has never failed for me. Hope this helps you out.

J