You feed them on a regural schedule. Every 5-7 days. You feed young BP's 15% of their body weight (so if your BP weighs 100 grams you should feed him/her 15 grams of rodent) for older BP's just feed them a rodent that is about the same width as the widest part of the BP.

A hungry BP usually will be out "hunting" at night. But this isn't a fool proof method.