OK here, I'll give ya'all a non lethal way to give the mutt one final chance. If ANY ONE CARES ANY THING ABOUT this nuisance after this they will fix it for you.

If you've got them eating your dogs food you are already more than half way home. Get some stuff at the auto shop called anti sieze. Make a little rail around the dog food where they have to rub up on it to get the food and then greeze the heck out of that rail with anti sieze. That stuff makes the worst mess you've ever seen and one drop get's spread EVERY WHERE. If that dog is a pet, it is going to ruin any body's cloths it touches when it gets back. Water won't wash it off even if he runs loose all day with it on and if he's an inside pet, well it's gonna make them wish they kept a better eye on him.

If that don't stop it, SSS.