Hey everyone!! I have a 5 1/2 year old Jack that was great with kids, people and other dogs. We moved and something happened when he hit 3 and started getting aggressive. We thought we needed an exorcist or something because he got possessed or something. He would be fine and all of a sudden would start growling at us etc. He snapped at me twice recently.
Anyway, he gets crazy when other dogs are around. He will start choking himself trying to get them all the while he is barking viscously. I try to get him to calm down by making him sit and what not, but nothing works. My wife walks him at least 4 miles every morning which is over an hour at a fast pace. The whole time she keeps him right next to her side, and he is fine. Any help would be really really appreciated!