I have a dog pen recycled for ducks, and I lined the sides with 4' by 8' sheets of clear plastic (poly?) 1/8 inch thick, so no raccoon
grabbers can reach them from the sides. The roof is covered with chicken wire- I know this stuff is not coonproof, but come spring, it will be enhanced. This year with all of the snow, the roof covering has been a non issue- frozen ice/snow has capped the pen since December. Just now melting. Find some used chain link fencing (Craigs list free stuff) and zip tie it to the bottom of your cages, laying the fencing flat on the ground.
It will sink in, but being galvanized will last quite a while, and being so wide, no critters digging in can get around it, or through it, and are too dumb to back off four feet and try digging again.
The cost is minimal and it sure is frustrating to the diggers. Grass grows through, and you can mow over- can't even see it after a while.