Do you know the measurements? For 2 sows it needs to be a minimum of 120 by 60 cm and for 2 boars it needs to be 140 by 60 cm.
My hutch is lined with lino so it can be easily wiped and stops the wood getting as damp
oh my gosh that sounds amazing!Why not take out two or three of the floors, turn it on its side, cut a small hole in one floor (big enough fora pig to get through) and put a wooden door on one end to enclose it. And Hey Presto! You've got a great big, roomy hutch!
You could paint the inside with a pet-friendly paint (perhaps white or cream to make it bright) and put lino on the floor, as has been suggested. I assume you were going to make a mesh door anyway, so you could get inside to clean out?