My youngest BP is 6 months old and has no problem taking adult mice or rat pups.
The bottom line is to feed a prey slightly smaller than the girth size (widest part of your BP’s body) once a week.
Also remember that prey size often varies, depending on the place you get your feeder from.
Most hatchling are started on hoppers and quickly move to adult mice, fuzzies are not appropriated for a BP.
There is no set schedule when it comes to a BP defecating, however you need to feed your BP more, next feeding try a medium mouse, see how it goes and see if an adult mouse would work.