Our dogs bark at ghosts as well and often there is something there we just don't hear it- maybe even a fan or something running she hears you don't?? I have used an ultrasonic pinger (from Amazon) -we don't hear it it but they do-- I touch the button as I say NO BARK-- the sound is unpleasant to them and it gets their attention. I have gotten them to stop or reduce their barking at me making coffee and sometime at phantom sounds (the ones I don't hear). It is a tool and should not be over used but if she associates barking at the neighbors with that unpleasant sound it might work. We had a bi black girl Shelite who was a nervous nellie and she was also a barker - maybe out of fear?? I think going out with her and stopping her barking is important or it will get worse and I am sure your neighbors don't want to hear it...I know one of mine who lives 80 yds away thru the woods gets very upset at mine when they bark at animals in the woods or people going by on the road or just playing with each other-- even for a brief time--She is a real problem and any day I expect a note from her lawyer. My dogs bark only sporadically and for relatively brief amounts of time.
