Switching to rats should help. A mouse is a pretty small meal for a BP. My hatchlings eat a hopper mouse for their first meal or two, then they're on to adult mice or rat pups every 5 days. I'd say feed her an appropriately sized rat (about as big around as she is at her thickest part every 7 days. You could also have her checked for parasites....it never hurts to check. How much does she weigh now?