Maddie does this with some people now and used to do it with almost everyone at first. For her it was not an aggressive bark but it seemed DEfensive. Sort of like she was trying to let those people know she was tougher than she looked.
For Maddie, socialization did the trick. We take her places with lots of people and have lots of people over to the house. We take treats on walks and have strangers who want to pet her give her a treat. Its a reward for being brave enough to go up to the strangers.
As long as the barking isn't aggressive I would try to let her get to what/who she is barking at. Once there's no mystery there will likely be no barking.
Tom |