Ecollar but you need to be 100% I mean 100% that pup is chasing a rabbbit. If he gives chase give him stimulation but do not say a word. You want him to think the rabbit is what is biting him. Not you. My GSP is 6years old when she was about 1 year or so I was in the in the UP of Mich. She jumped a snowsshoe hare. I happen to be standing there in plain sight. She passed by in full pursuit. I gavve her full stimulation. She broke off chase looking like the devil got her. Was in Texas 2 years later my friends GSP jumped a Jack rabbit. My dog completely the other way.. Sh wanted no part of that rabbit...[/align]