Well, I think the best thing to do is
- Always leave your door shut when you arent around.
- Get a baby gate for when you are, and if you dont want to, how about getting a high playpen for like, rabbits, and puting it around the cage.
And training your dog. I dont think shock collars are completely neccesary from what you have said about the dog, but Im not against them totally. I have one for my dog. Its an electric fence. Why? Because its the humane way! I would rather a tiny zap, then being hit by a car! I my self have walked through it, and gotten zapped. No big deal at all. Its harmless if used right!