Some great responses here! Thanks!
Okay, so what I did .. *L* .. I told you that I had brought Trick in and she was in a down-stay. I left her there and walked over to the owner (talking to her was difficult across the room as her pup barked SO DARN LOUD! *L*). The pup ignored me, was still at the end of the leash barking.
My assessment of the situation is that this pup didn't have a clue as to how to act. He had some fear, possibly brought on by an experience at the boarding kennel (and possibly during a fear period). His reaction now was to lunge and bark and he was learning that not only would dogs go away from him, but that his Mom would pull back on the leash and be his support.
So I asked the owner to drop the leash and walk away. I wouldn't recommend this to anyone unless they have a very secure dog (like Trick). Trick is a pretty amazing girl - she is the one we use in the puppy classes to stop the overly rambunctious pups. She's dominant but in all the right ways. Not aggressive but she will use her body language to "explain" the proper behavior.
The owner looked at me and I said "Trick is okay. Drop the leash if you're comfortable." She let go of the leash and turned away and her pup immediately stopped barking and turned to look at her. It was actually kind of funny .. *L* .. he barked a time or two at Trick and then turned and followed his Mom. No barking, hackles down at this point. I had her just leave the leash loose.
She was amazed. But so much of fear aggression is fueled by the concept of the "pack support" behind the dog, and that's communicated directly to the dog by the leash. Without holding the leash, there was no longer that communication and the pup stopped because he no longer felt he had the back-up.
I told the owner to reward any "positive" behaviors the pup offered from this point out. She was to click and give him treats when he looked at her, or when he ignored Trick, or did a sit, etc.
Then I released Trick from her stay. She came over to us, the pup hackled up a bit and barked and she ignored him. She came to me and I gave her a treat, and the pup stopped barking because she didn't even look at him at that point. He came closer and was curious and she turned to look at him. He was cautious but we humans just stood back and let them interact. Trick went to him and sniffed him, he hackled a bit but she just ignored that for the most part. When he got a bit pushy, she shoved her neck over him and pushed him back.
Before too long they were wandering around the room, going from person to person to get a treat. So I went out and got another dog - my young chow who is 21 months old and FULL of energy. She was also in heat and wearing "undies" .. *L* .. I expected that this pup was too young to react, but if he did I would have taken her out right away. As I was going in and out the door, I had the woman pick up the leash so that the pup wouldn't sneak out. When I came back in with Khana, he again lunged and barked. She dropped the leash and he stopped.
I turned Khana loose and she raced over to him and he ducked away from her in surprise. She is SO friendly and kept running past him and finally enticed him into a game of chase and play. He was hesitant and almost didn't know how to play, it seemed. Khana ran circles around him.
Soon after that another person arrived for the next class, with a young Airedale. Again, when the GSD pup's owner picked up the leash, he started barking but it wasn't as nearly as frenzied and she was able to back up and have him follow her so that she could reward him. He definitely was showing an improvement already. Within a short time we were able to turn him loose again with the Airedale too (and Trick and Khana still in the room). The four dogs wandered around and interacted peacefully.
I've found that most of the time, with young dogs, they just need proper interaction to understand how to behave. We don't know what happened to make him act fearful, but a dog like Trick is invaluable when it comes to helping pups like this. Trick is so solid, so reliable that we can turn her out with a fearful pup and she will not react badly if the pup acts stupid (lunges and snaps, etc.). When the pup realizes that there isn't a problem and relaxes, then it's time to up the criteria a bit by adding a dog with a higher energy level. Next week we are meeting again, and I'll bring a couple of other dogs so there are some new ones there.
And the woman's assignment was to find a safe playmate for her puppy, and to continue to reinforce the "good" behaviors. A good part of the whole procedure is showing the owner that they have a normal puppy with some slight fear issues, but who is capable of interacting without a problem. NOW is the time to work with this, and I'm really glad that she didn't wait until this pup was a year old and completely out of control.
I am a strong advocate of early socialization - early as in before they ever leave the breeder. And I encourage everyone to go to puppy classes and to socialize throughout the dog's life. There are some out there who say "my dog never needs to meet another dog!" and I strongly disagree with that because meetings between dogs DO happen. It's our responsibility to provide the dog with the tools in how to understand dog language and proper behavior, and that's done by socialization during that early developmental time and continuing on from there. Training classes are so important and I get mine out at the age of 8-9 weeks (yep, that young!) and keep going to various classes. This is why Trick is as solid as she is (that and good breeding). This is why I have chows that can be taken into a mix of dogs and turned loose, with no fear that they'll start anything with anyone.
I expect this GSD pup will be just fine. The desensitization that so many mentioned is another option if there isn't a dog like Trick around. But I really recommend getting the dog off-leash even if you have to put up an exercise pen to separate the dogs. It makes a huge difference to most dogs when the leash pressure goes away. I've worked with many "aggressive" dogs (almost always fear aggression) and we would put the dogs behind an ex-pen and then reinforce for all non-aggressive behavior. Nearly all of these dogs were able to integrate into a normal class situation after going through these sessions.
Melanie and the gang in Alaska