I adopted Sadie Lou(lab mix) a few years ago and she came into our family with our existing dog (GSD mix). She was noted to have separation anxiety where she was before but didn't really show any in our home. She has been good but barks more than I like. Within the past 6 months she has been barking more intensely and several times has attacked or tried to attack my GSD when they are both barking at another source. I am perplexed why she is suddenly doing this.