My yorkie is almost a year old. My mom recently got a yorkie puppy. They are both female, my mom has kept Milie once for week while I was out of town, and my mom has brougt her yorkie to my house when she visited for the weekend. Both time they got along great. The other day I had to go out of town again, when I took Millie to my moms she atacked my mom's dog twice within minutes, and I couldnt leave her there and had to board her. I as wondering if any of you could tell me why she was so agressive when she has been with this dog many times before.
