I have 3 collies, 12 years, 9 years and 1 1/2 years. As a rule they all get a long, there is no fighting over food, bones, toys or me for affection. They are all well socialised and the older two have competed at flyball all their lives. A year ago I moved in with my partner and the upset of moving seemed to cause a few fights between the two older ones with Buster (12 years) needing stitches after one episode. All has been quiet for the last 12 months. My problem is with the middle dog who last week, twice in the same day (hours apart) went for my old boy. I know dogs have there squabbles but when Ceillo goes for another dog it is without mercy. It is the intensity of the fighting that is up setting me the most as now I can no longer leave them together with out worrying Ceillo is going to start something!