What is possible?
In this picture, Molly and Bailey, who are working Patterdales, have spied a squirrel which is on the ground just behind the pedestrian on the left. Notice that the leads are both loose. They focused on the squirrel for 30-40s and then Julie asked them to come with her which they did.
There was no pulling on the lead, no corrections, no shouting, just careful monitoring of the dogs, their body language and the environment. No need for an e-collar or a prong collar.
Some trainers say you can’t do this without using aversive training. You can. Start on the lead, then on the long line, training using cues and reinforcement principles along the way. Then graduate to being off lead in some circumstances then in all circumstances. Realise you will make mistakes. Learn from them, regroup and move on, improving all the time.
Dogs can learn when they can chase, when they can’t and a whole bunch of other stuff. This is all done by forging a deep relationship built on a long history of positive reinforcement and giving your dogs an outlet for their needs.