My Jack Russell Miley came from Battersea dogs home a year ago, she is 11 years old, we live in a sheltered home complex. With us she is a loving gentle dog and allows us to do anything to her and loves sitting with us having her tummy tickled. she goes out for walks at least once day mostly two or three. apart from toilet breaks. She mixes with other dogs who live here and is happy playing with them. She likes all the other residents when we are in the general lounge, sitting on their laps, but if a stranger or even one of the residents comes by with a bag or parcel she runs up to them aggressively barking and snapping at them, When out she does the same to other dogs. This has got worse and worse over the last couple of months. she changes from a gentle happy dog to a aggressive monster i find her diffcult to handle as she will snap the lead out of my hand we keep a muzzle on when she is out as a precaution. we know she has had a bad time in her life and has been to Battersea at least twice and is close to being returned again as i am going to have an operation on my knees and wont be able to walk for a while and my wife is disabled so can't do it. Please give us some advice as we are desperate and want our loving dog to be able has live out the rest of her life as a happy dog. I wondered if she is ill in pain or some sort of mental health problem.