RESOURCE GUARDING (GREAT POSTER)

To stop the development of resource guarding, teach your dog to tolerate the presence of people and other animals around his food bowl, toys, bed and other things he might regard as his and being possessive or place a high value on these things
BUT RECOGNIZE THE BODY LANGUAGE (ABOVE)

Teach your dog to trade good stuff for better stuff, then give him the original good stuff back. You want him to respond positively.