Good luck with that one.The one weakness with dogs is that they are susceptible to poisoning, .
The only access is the letterbox and those who own big dogs know that
to give a dog access to that is asking for trouble. Either chewed up mail
or chewed up postman/paper boys hand. To poison the dog you'd have
to break in and to do that you'd be in his zone already.
(mine can open doors BTW)
Once you invade that, you can have the best prime steak going and the
dog wont care. Food response is gone and you are now on defend/attack
Besides the scrotes always go for the easy target and the house next door
that has no dog is far more atractive than the one that does.