[mscat]

I added a female shih tzu when my Suzi (yorkie) was a year old. They have had no problems at all. My vet told me I should have goten a male though, because females sometimes do not get along well. Sense yours is a male, then adding a female would probably work out fine. Maybe you could allow them to meet beforehand, just to make sure they get along well. my brother and sister in law just got anther puppy for the same reason. Their other young dog was lonely, now they are both very happy dogs together. I think it is typical a senior dog would not like a puppy around. That happened to us a long time ago when we brought home a new pom puppy, and our older pom was not happy.