Aggressive behaviour towards visitors
Our Jack Russell is 2 years old. She is becoming more aggressive towards visitors. Firstly when she hears a vehicle coming up the driveway she starts to bark. In fact most noises make her bark.
When someone knocks the door she go crazy, hairs up on her neck jumping and barking at the door. Today a workman came in and she was very aggressive towards him, charging towards him and barking and growling. I sent her to her bed where she sat but continued to threaten him. When he worked I released her and tried to reassure her that it was okay, with strokes, etc. She still acted aggressively so I sent her away.
Her barking at noises is increasing and her aggression levels are increasing. When she is in the garden she barks at any noise or movement.
What is the best course of action to take here?