Hi Frank,
Most dogs will bark at anything that seems foreign to them. That's what they do. They are dogs. However, barking can be a problem if it becomes excessive.
To help you address your problem, I need to know a few more details related to your dog's barking problem. Is he crated/chained while he is barking at these people? Has he had any bad experiences with any of the people/dog he's barking at? Does your dog know any basic commands? Sit, Stay etc?
Before we can address the barking, we need to first identify the triggers that are causing the barking. Once we have the triggers, there are techniques that we can use to easily fix this problem.
Rubini M
Certified Dog Trainer, ABCDT
Animal Behavior College (USA)
member of Association of Pet Dog Trainers
email:
doggonegoodtraining@live.com