I have 3 dogs whom all live inside 1 female jack russell, 1 male jack russell, and 1 male terrier mix. They have lived together for over a year now without any problems until recently. The female jack russell has become extremely agressive almost territorial towards the other dogs. She attacks the for almost no apparent reason at times.. They all get equal amounts of attention and exercise so I am truly at a loss on what to do. Any advice?