Some dogs start showing resource guarding behaviour as young puppies already. These dogs will growl when one comes close to their food bowls and will even snap when a human approaches. Many people like to ascribe resource guarding incidents to dominance, which may lead to dogs being labeled incorrectly. I believe that this is behaviour that can be prevented.
We can start off by using the exercise 'Give' when we trade the dog whatever he has in his mouth for a high value treat. Whatever he has in his mouth can be clothes, a slipper or anything that was supposed to be in a cupboard but which was stumbled upon by puppy. The more I wrestle him for what is in his mouth, the higher the possibility that he will see it as a game and be reluctant to give it up. If your dog presents this behaviour whilst he has something of high value like a bone in his mouth, puppy can become dangerous when trying to protect what he sees as his. The added value of the 'Give' exercise is that puppy can develop a very good retrieve exercise, making playtime more fun. Yes, puppy has my slipper; I take a piece of chicken and ask him to give, showing him the chicken. The moment he lets go of the slipper, he gets the chicken. The purpose of doing this is to teach puppy that giving up something is not necessarily bad and he does not loose it. When we work to prevent resource guarding, we trade puppy for a higher value treat and give whatever we took from it, back. (And see if you can read puppy's thoughts - 'wow, these humans are strange - she has just taken it from me and now I have that AND this cool piece of chicken/meat/liver bread) Puppy has a bone, I ask him to give, take it and trade him for something better. Once he has given it up, he gets his bone back.
We start off by feeding puppy his entire meal by hand from his bowl. He sees you taking the food from the bowl. Different family members give puppy his food from the bowl. In this exercise I combine what Miller says with Donaldson and Dunbar's suggestions and ask that we gently touch and handle puppy while we hand feed it. Puppy learns that having humans around when I eat is actually quite good.
We now move on to having a second bowl available. We put puppy's meal in the first and take part of it and put it in the second bowl. You keep putting more food into the bowl, showing puppy that hands near the bowl is a good thing. Hands near my food bowl mean more, not less food. After this we put part of the meal in the bowl, let him eat, ask him to give, take the bowl away, trade him for a high value treat and return the food bowl with the rest of the food. Reminding puppy for the rest of his life that humans near his bowl or when he is chewing something he is allowed to eat, swallow and digest is a great thing, will help the family stay safe.
The purpose of doing this is to teach puppy that giving up something is not necessarily bad and he does not loose it.
Donaldson, J: "The Culture Clash" James & Kenneth, Berkeley, 1996
Dunbar, I: "Before and After you get you Puppy" James & Kenneth, Berkeley, 2004
Miller, P: "The Power of Positive Dog Training" Wiley Publishing, New York, 2001