If you are feeding fuzzy mice you are underfeeding.
BP do not have a schedule they go whenever they need to, it can be a few days to a few weeks, what you want to look for is signs of impaction which would translate in a bulge near the cloaca.
Hatchling are using most of the prey item for their growth therefore it is VERY important to feed an appropriate size prey, hatchling get started on hopper mice or crawler rats so either way the prey offered is not adequate for a 1 month old animal.
No food or inadequate food size = no defecation.