i rescued my yorkie from a shelter and when we go to walk and people stare at me he starts to growl and bark?

Dogs communicate through body language and barking. Your dog will bark for various reasons, if he wants to go outside, if he thinks you’re playing with him and, unfortunately, if he is wary of strangers. A dog that barks at strangers does so out of fear, and a fearful dog is more likely to bite. When your dog barks at strangers, it’s imperative that you take steps immediately to correct the situation.
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Staring by anyone is threatening behavior to a dog - when two dogs stare at each other, it's a precursor to a fight breaking out. (Why are people staring so much)?

The key is to distract your dog before the behavior starts. You have to be alert for situations that might set your dog off. When you see someone approaching you, distract your dog with a treat or a favorite toy before he acts up. He will learn that approaching people means he gets a treat and he will calm down. You might want to practice this with a family member or a friend so you get the technique down before going in public.
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This is normal behaviour of a dog that has never been trained. This is also normal behaviour of an owner who wants attention for rescuing a dog like the rest of have done without seeking the attention.
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