If you use an insert of coroplast for the bottom of your cage(one that is removable) you can place your towels or underlayment then you fleece on top. Turn it over and use packing tape to tape it to the cororplast nice and tight. Then turn it over and place it back in the cage. Your piggies willhave no way to get under the fleece. As an added measure you can use the binder clips to keep all layers from shifting. My piggies were ver similar and now they also have a sleep loft that is covered in fleece. THis has a roof so to speak and is now a new hide out place. Aslo mine like small fleece blankets that they can bury under. Here are two photos of what I am talking about. Hope this helps.
