My nearly 2 year old Lhasa Apso has started to present behaviours that indicate food aggression and resource guarding. It seems to have started when I got a kitten. She is a dominant dog within the home but outside with dogs she doesn't know is nervous and if pushed will become fear aggressive, although this is a separate issue and she is improving dramatically. She is fine during meal times and will eat very close to my other dog with no problem. However recently she has started to become aggressive around treats and high reward food. It started when I would give out treats she would snap at my other dog and chase the cat away. I started giving treats out with a good distant between each animal and she stopped, it was only when they got too close. So I avoided these situations so she couldn't practise the behaviour. However now the problem seems to have escalated, for example I was sat eating some chocolate and my other dog simply walked passed me and my Lhasa Apso lunged at her. She bites but doesn't bite its more of a warning and will stop when they have backed off. I reacted by shouting No and simply told her to get out the room. She is also quite protective of my room.. Doesn't like my other dog or cat entering and again will present the same behaviour. She is fine with people and children, no aggressive behaviour or resource guarding there, just other dogs and the cat. What can I do to help stop this behaviour? I don't it to get worse as she may end up hurting my other dog or cat. I will also add that she is not spayed as of yet which I am aware can contribute to the problem, but she will be getting spayed. The training methods I have used since she was a puppy are all positive reinforcement as she does not react or understand negative punishment, I also prefer positive reinforcement.