Fearful behavior
Young dogs usually experience a new « fear period » around puberty (they had their first fear period when they were puppies). It may be very surprising that your seemingly confident and friendly young dog is suddenly afraid of things he was not afraid of before, but try not to worry too much because this is usually a temporary phase and all he needs is your understanding and support.
Review socialization information, paying special attention to areas that might be of concern to the dog. Be sure to gradually address the things that worry him, at a pace that is comfortable for him.
At this stage, avoid potentially stressful events such as kennel time, attendance at a well-attended national show, or spaying or neutering (except in emergencies, of course) and try to keep things consistent, predictable, and safe for your dog. Although it can be worrisome if your dog is a little more excited than usual, try to remain calm and relaxed in his presence. He is very perceptive and you don’t want to give him additional cause for concern.
Chew
Although your dog probably already has adult teeth, he may feel uncomfortable when these teeth grow into his jaws. Expect him to need to chew more intensely at this stage, and be sure to give him plenty of opportunities to practice this important behavior. The good news is that chewing is calming for most dogs, so everyone benefits!
Training
Regardless of the persistence of your dog’s « bad habits, » be persistent and consistent in training and you will benefit in the end!