Keep him on a leash, I too have the crates of heavy plastic, and NEVER EVER leave them out w/out a leash or unattended in the crate fence...I am in the kitchen and they are right out the door, I leave the kitchen door open so they can come in and out while I am cooking, etc. Or take it out by the garden when I am gardening and want them out w/ me...Sorry to say, but some of these things are No Brainers!