As most of the folks in our club, I have multiple dogs as my "personal" dogs, those that also live in the house with us. As I've been working more with my Dutchie, "Becker", I've been noticing a slight problem between him and my JRT "whip". Because I've noticed it, it will NOT become a problem, but if you are working one dog more than another, and especially in a sport like French ring, where we are manipulating all sorts of "drives" (pack defense, possession, resource, prey, blah blah) you might run into a fight or two at home. Not much different than what happens when a police K9 lives in the home, and there are other pet dogs that live there, too. I always find it facinating that everything we do with our dogs has impact in other areas of training, interacting, and just plain living!