What amount of food aggression/protectiveness is appropriate with three dogs eating together? If any? I'm seeing some occasional snarling, growling, and barking lately with high value dinners and treats but no real fights. I feel like some "protecting" of their food is warranted, but where do I need to step in (even to the point of just saying "chill!")? None are food aggressive with humans and I can always take things away with no protest.