Your post reads as if you are planning on them living them indoors still - their time outside will be limited to when you are out there. If so, is it possible/have you thought about putting them in a run while you are out there rather than in a hutch? That way, you don’t need bedding (just a handful or two of hay available while they are in the run) as they can be directly on the grass (once tummies are used to it)
I have outdoor/shed piggies and rabbits - but they are permanently out there. They are in three hutches (two of which are 6 foot hutches (one is a double storey), one is a 5ft) . Mine are bedded on an absorbent layer of megazorb (although i also like aubiose), and then all topped with hay.
You don’t need to change out all the bedding hay daily. Simply poop pick and remove wet areas once or twice a day, and then throw in a handful to replace it (while ensuring there is plenty for them to eat). The whole of the bedding hay only needs to be replaced once a week (twice at most if they are very messy).
As a rough guide , I use 15kg of meadow hay for bedding and eating, plus a further 5kg of soft timothy for eating, every three/four weeks between three hutches (five animals). (With less thick amounts of bedding hay being used in summer when their need for the extra warmth is less)
