clicker training. trust me Happy has fear agression, it used to be so bad she would lunge and bark and try to bit anyone(mostly kids) who walked by, now she runs to kids happily wanting to play. before clicker traning we could not get her near a petstore before she started barking and lungeing after 2 weeks she was sleeping inside of one. you need a clicker, lots and lots of very tasty treats, and another dog. a dog that is familier though at first. have someone else hold the other dog on leash, then you need to start a good distance away with chewie on leash, everytime she looks at the other dog without barking or lunging click and reward, keep doing this till she gets the idea, then start moving closer to the other dog very slowly, if she cant take it anymore and sarts barking and lunging then you are out of her comfort zone, so move back and work some more just at the edge of her comort zone, the idea is to start shrinking her comfort zone over time, this may take a while but it works, once Happy was comofrtable with the first dog we started to figer 8s with Happy on the outside then switched to the inside so that Happy was walking right past the other dog, continuing with lots of clicks and treats. then you switch dogs and start all over lol this time it may not take as long as the first, keep working with her, take her to lots of places, with treats and a clicker, I would sit outside of a supermarket with Happy and lots of treats we scared a few people lol but lots of work, treats and praise really paid off. but whatever you do NEVER punnish a fear aggressive dog for lunging and barking, that is the worst mistake you can make, because makeking the dog more scared then it already is will do nothing but make the problem worse(yes we made this mistake lol)