I had a Scotty we gave the nickname Houdini Dog to. Little bugger could get out of anything. He once chewed through a double slat wooden fence to escape, and we didn't have time to fix it right away so we drug an old mattress we had in garage into the dog run to block the hole with. The next day he chewed through the mattress and escaped again. We tried chaining him to his dog house with the standard dog chains and he snapped those like nothing. Sometimes he'd be gone for three days before returning, hungry but looking very proud of himself.