He’s not pooping because he is using everything you’ve fed him, your prey size is way too small. A ball python should never be on a mouse fuzzy. Right out the egg hoppers are perfect size and after 2-3 hoppers I already move them to rat fuzzies so they don’t get used to mice. Once you start feeding an appropriate sized meal, he should start pooping a little more often but they really don’t go that often even when they are fed correctly, it’s amazing how efficient their digestion is. Weigh him and then feed him according to the chart the other member just posted, that should get you on track.