The dog has become progressively more and more independent and is harder to control. What often happens is that the trainers will suppress the prey drive with pressure. When that happens fight drive often appears. One would initially think that this is OK because in reality this is what we are trying to accomplish. The problem is that this fight drive is very situational and not spontaneous.
All behaviors have thresholds.
A threshold is the level of stimulation that triggers a certain drive or behavior. It is impossible for a new helper to work dogs in defense unless he has a clear understanding of the thresholds for prey, defense and avoidance on each dog he works. If your goal is to learn to work a dog in defense, you need to start to learn everything you can about recognizing thresholds. Knowing when a dog is approaching his threshold to avoidance is critical for defensive training. In dog training we will talk about low, medium and high thresholds.