It's difficult to find fault with the animalss in the above situation. Dogs are wired to be territorial and will be aggressive to protect their pack and location. Imagine how confusing it must be to be transported to a strange place with 1000's of foreign odors, some of them from animals present and some of past visits.
Thankfully, the old Shepherd made it through without a serious bite. Lucky, too, that the Shepherd they tried to attack wasn't a dog that had a history of defending himself against other dogs. If the small dogs had tried that nonsense against some Alaskan Malamutes I've been in contact with, there would have been a much different outcome.
Glad to hear that your buddy is OK and on alert in the present situation.
