TIP #1: SET YOUR MULTI-DOG HOUSEHOLD UP FOR SUCCESS
Living with multiple dogs brings a whole new set of challenges. Adding a second (or third, or fourth) dog means more fun, more love, more joy and more wonderful doggy companionship. But it also means much more from you: more time, more money, more energy, and more working through problems.
Expect your dogs to get along, but avoid taking sides if they don't. Scolding a dog for initiating a conflict could easily backfire. For dogs with inherently good social skills, let them negotiate minor, nonviolent differences without interfering. If the dogs are headed toward a major confrontation, however, you can step in and redirect the dog's behavior before the conflict escalates.
TIP #2: WHY OTHERWISE FRIENDLY DOGS MAY BEHAVE AGGRESSIVELY WHEN ON-LEASH
If you hang around with other dog owners, you've no doubt heard the same comment I have, over and over again: "My dog is fine with other dogs when he's off-leash; he's only dog-aggressive when his leash is on." You may have even said it yourself.
The reason it's an often-heard comment is that it's a common behavior: A lot of dogs who are fine with other dogs when left to their own devices become aggressive if they are leashed when they meet other dogs.
We know that aggression is caused by stress. Clearly, there is something about being on a leash that a lot of dogs find stressful enough that it prompts aggressive behavior. There are several reasons for this. Let's take a look at one of them.
Leash Interference with Normal Social Interaction
Picture in your mind two dogs meeting and greeting, off-leash. They engage in a social dance - advancing, retreating, moving around each other, sniffing various body parts, giving body language signals intended to keep the interaction civil. Sometimes the movements are slow; sometimes they are quick. If one dog is cautious or fearful of the other, he can retreat as he wishes, using social distance to keep himself safe.
Now picture those same two dogs meeting on-leash. The dance is stilted, inhibited by the restraint of the leash. One dog tries to circle the other, and the leash tangles around his legs. The cautious dog would like to retreat to safety, but knows the leash restricts his movement, and elects to act out his second option to increase distance - a growl and a snap to signal to the other dog to move away - who cannot, because he is leashed. The fight is on.
In the future, the cautious dog will offer a growl and snap before he's close enough for the other dog to make contact. The best defense is a good offense. Alarmed, owners move away from each other, and the fearful dog's aggression is reinforced by the increased distance. Behaviors that are reinforced repeat and increase, and the cautious dog's aggression escalates as he realizes that it's a successful behavior strategy for him - it keeps other scary dogs away. You now have a leash-aggressive dog. Absent the leash, he still chooses to move away from the other dog - his first behavior choice.
- Whole Dog Journal
Jeff Dentler, CPDT-KA, IAABC-ADT, FFCP, CTDI