There are quite a few members on here that feed their adult BP's mice for one reason or another. So the fact that the BP eats mice in general is not a bad thing, as long as it's 1-2 adult mice once a week. A BP should experience the same growth rate as it would if it were being fed 1 small adult rat per week.

Before you decide to breed your BP's, I would definately see if you could get an exact weight on her, because if the female really is 1 lb, there is something majorly wrong. Has this BP been in your teachers care for all 5 years, or did they recently get it and was told that it was 5 years old? Have fecals been done on both animals to check for any parasites that they could pass to each other? How are you going to house the babies once they hatch? Who are you going to sell the hatchlings to, and how will you market them? Those are just a few things to keep in mind while you are still considering breeding BP's.