I put down that comfy rubber mat that you find at gyms in squares. Well before I could get it all glued down for safety they both chewed and ate the end cover strip... Some got thrown up and the rest came out in the poop. And then they got another type of rubber mat, but just a little. Pooped out... I have moon mat glued down in their room. Not as nice and comfy as the rubber mat.. But after a month picking up poo checking for rubber they will have to make do. Vader is the chewer, Reya not so much, but if he has something going to town on, she feels obligated to join in. Oh well. I keep an eye on them and make sure there is nothing on the floor for them to chew other than there toys.