I would not trust an invisable fence. With any huntong dog the need overrides the pain and the first time she gets running she will shoot right across that line, get shocked once and then nothing. She will learn that it is a small pain for the fun of chasing chicks. The idea of free ranging your chickens can still work, you will just have to free range when you can be home for a few hours and the dog can be tied up. Train the chickens will be easier then training the dog. She will be fine as long as you are with her but it is just to tempting for her breeding to not chase, and then kill... Teach the chickens that the dog is not safe and that at certain time in the evening it is time to go into the coop before the dog comes out. My chickens knew that when my hubby got home he would let the dogs out to do chores and they would all go into the barn to roost. I dont have to worry about my healers killing my chickens anymore, I have taught them to leave them alone. It took a lot of yelling "NO" and "OUT". We have a lab mix that will leave them alone if we are out but not if we go into the house. The coon hound get tied up no matter what so if the chickens go into her space that is their fault and they better run, she has actually never killed any, just scared the feathers off them..lol If your dog is a bird dog you will probably never bea able to totally trust her. It depends on how birdy her breeding is. If she comes from working parents the you probably wont. You will have to compromise with both the dog and the chickens and give them both free time. She might not chase quite so much when they are adults either. Jenn