If you want to learn more about training and controlling your Jack Russell, my ebook is bound to save you hours of training trial and error and relieve a lot of stress from the process: The Jack Russell Lover's Ultimate Guide to Training comes complete with a full chapter on mix breeds.
Aggression with my Jack
My Jack Russell Terrier, Cooper age 22 months has become aggressive about being groomed. Last week the groomer called and said come get him we can't finish him. Yesterday I tried to remove a tick from his back and he became very upset with me, growling and snapping.
He previously had an issue with sudden movements, but I think we have resolved this.
Any suggestions are appreciated. He's a real sweet dog and very affeciate when he wishes.