Recently (past 3 months or so) we've been having some aggression issues from our normally sweet dog. She is a 4.5 year old Boxer/Pit mix. She gets plenty of running around, lots of bones and chew things. I've taken her to the vet to make sure there were no under lying health issues, none were found. I am at a loss, she used to never growl and bark at people and now I can't let her outside without me because she will chase any person that is outside. We are getting new neighbors in a couple months so I'd like to get this under control. Any recommendations for behavior training or at home things we can do would be greatly appreciated!! Thank you in advance!