We have 4 ft. chain link and the dogs have a dog door. We are fortunate that ours are not escapers, they are older couch potatoes but even as youngsters they never tried to escape. Ours have outdoor access 24/7, whether we are here or not, which is nice if we get tied up and are away from home all day. I agree with Sharron, in my experience, single dogs are more likely to go looking for adventure!
Anne in Tampa