Dog Training/Dog Aggression
My family owns two golden retrievers (8 year old female and 6 year old male), both well behaved. The female is the alpha dog of the family. We recently adopted a five year old male shih tzu. We received the dog with no hair, several infections and an unknown past. For about two months the dog was very well behaved, with little sign of abuse, other than putting his head down before a person were to pet him. He never had problems with the other two dogs until the third month. Whenever in a person's lap, above the other dogs, he turns into a completely different dog. He suddenly turns aggressive as he growls/barks at only the male dog. Now, the dog growls on any level and has come very close to attacking the other dog. What suggestions do you have?
First, be sure that the Shih Tzu is healthy and feeling good. Sometimes dogs will aggress toward other dogs to keep them away because they are afraid of being hurt. This is especially true of small dogs who live with bigger dogs.
After you're sure he's not hurting, you can start to associate the approach of the golden with good things happening. Do set-ups where the GR walks by on leash and you feed high value bits of food to the ST. When the GR comes is in sight, food happens. When the GR moves away, food stops. Ideally, the GR should be at enough of a distance that the ST is not already growling/barking. Be sure the the food is something the ST really likes - usually very small bits of cheese or chicken are good choices. The bits should be no bigger than 1/2 a pea. You should get to a point where the ST sees the GR coming, then looks to you for the food. You're changing his emotional reaction from one of fear to happy expectance of a food treat. You should start to see changes in his body language as well.
My other advice to you woud be to keep the goldens and the ST separated except for when you are able to supervise and monitor 100% of the time. Always have a safe place, like a crate, that the ST can escape to and the GR's can't bother him. Don't allow the ST on your lap when the golden is in the room and don't punish the barking and growling. Take the information that the ST is uncomfortable and remove him from the situation that's causing the stress.
These dogs probably aren't ever going to friends and playmates, so don't put them in situations where this could possibly escalate.
Please let me know if you have follow-up comments or quesitons. Good luck.