Our 6 yo Aussie is very docile and social. Loves our other dog, and gets along well with our son's long hair chihauhua. Put recently the chihuahua growled at my wife and our Aussie attacked him.they were seperated with no physical harm done. It was tense for a few days where we wouldn't leave them alone when they were together. My son moved to his new house and after a couple of weeks brought his dog over. After a couple of hours our Aussie just went after after the chihuahua for no reason.
Question one, why would he do this? And two, what can we do to correct this?
Thanks in advance