I keep mine on paper, knowing that 48-72 hours after they eat a waterlogged rabbit they will need a full clean-out, and another the following day, and another the following day...

They're big snakes with fast metabolisms, and they eat big meals, so they make lots of big messes.

Wait until they're big enough to eat whole chickens and you have to clean poop-covered feathers off of the enclosure ceiling.