It appears to be tissue or something spongy. You can see the evidence at the bottom of the picture. Actually, I think it's the blanky they're standing on.
My cages are 695 modified,pull out trays and bigger doors. I remove the sides and attach three together. The tray has been replaced. They chewed the other one and have slowly started eating the other two. I could only get galvanized though from a sheet metal company here. Here it is
Those naughty ratties have chewed up that pretty quilted tunnel??? :evil:
They'll have to be assigned cleanup duty, issued with little brooms. :lol:
By the way, I can well imagine that the three 695's is a winning combination. I once had two 695s together, and that made a wonderful cage. With three cages they have so much room to run. :tracks: :tracks: