re: Question about dog starting to growl

Is the growling just surrounding possessiveness? Where was he and what was the situation when he growled at your FIL?

It's really hard to say without knowing the dog's history/personality. I had a dog that started exhibiting a little bit of possessiveness around food/bones just shy of his first birthday. My solution was gradual, but I basically started by feeding him out of my hand. At first, he ate but did so very tensely. The second I could tell he relaxed, I would praise him. After a few days he would eat out of my hand completely relaxed. I then transitioned to the bowl and would put a handful of food into his bowl and continually feed him as he ate to try to create a positive association with hands and food. I required him to sit, then I placed the food bowl in front of him, then released him to eat. Once he got comfortable with that, I would then place my hand in the bowl while he was eating sometimes.

Over time, his food possessiveness went away. Another method is to spread food out all over the floor. The idea is that this confuses the dog and he no longer has a small place to guard. Most dog behaviorists will tell you that you should not take the dog's food or bone away in response to aggression. I've never had a really serious issue with it so I can't speak to the merits of that theory, but I never took his food or his bone away from him. I just gave him bones less. The consensus, however, is that you should not address the issue with force as it is likely to compound the problem, which could be dangerous for you.