My first choice with most clients is this: changing the dogs’ opinion of each other through counterconditioning and desensitization (CC&D).
CC&D for intra-pack aggression involves changing your dogs’ association with each other from negative to positive. The easiest way to give most dogs a positive association is with very high-value, really yummy treats. I like to use chicken – canned, baked, or boiled, since most dogs love chicken and it’s a low-fat, low-calorie food.
Here’s how the CC&D process works:
Determine the distance at which your dogs can be in each other’s presence and be alert or wary but not extremely fearful or aroused. This is called the threshold distance. If one dog has a greater threshold hold distance than the other (often the case), work at the greater distance.
With you holding Dog A on leash, have your helper appear with Dog B at threshold distance “X.” The instant your dog sees the other, start feeding bits of chicken, non-stop. Your helper will feed chicken to her dog, too, the instant he notices your dog.
After several seconds, have the helper step out of sight with Dog B, and you both stop feeding chicken.
Keep repeating steps 1-3 until the sight of the other dog at distance “X” consistently causes both dogs to look at their handlers with a happy smile and a “Yay! Where’s my chicken?” expression. This is the physical presentation of the dogs’ conditioned emotional response (CER); each dog’s association with the other at threshold distance “X” is now positive, so they can deliberately look at you to get their chicken, rather than staying intensely focused on each other.
Now you need to increase the intensity of the stimulus by increasing the length of time Dog B stays in sight. Continue to feed chicken when they are in view of each other, occasionally pausing to let them look at each other again, and immediately feeding chicken when they do.