I have Pickle a 4yr old GSD female that is food driven at home but out in the fields when I'm trying to get some sorely needed training done she is totally uninterested in fact if I put the treat on her tongue she will spit it out even if there's no distractions She will chase her ball & is not so much possessive but reluctant to leave it or let me have the ball how ever if another dog is to close the interest in her ball goes totally out of the window. She is a working line with a prey drive that is extremely strong & is uncontrollable if she decides to chase bearing in mind I've had numerous training groups try to break her concentration (on the other dog usually) on the target. I have watched & learn't from those trainers & continued with the training but still she will concentrate on the distraction with an unwavering stare. I'm at a loss with her I have had many rescue dogs (I've had her from 8wks) & with perseverance I've at least gained some control but not with Pickle. Any suggestions! I hope I have explained the issue fully.