I had this same problem, just a couple weeks ago. We are fostering a beagle, and I caught her in the chicken pen. Beagles are notorious for bird hunting. While we were taking care of the chicken, she got in again and massacred most of my flock, including my best rooster (though he did fight quite hard poor guy). I don’t like the idea of shocking a dog, especially one I don’t own, but I did it anyway. It worked almost instantly. I put the collar on, and as usual she walked right over and started trying to open the gates. I have her a warning, she ignored, then one good shock and she is now staying far away from the chickens. Just make sure that she doesn’t see that you have the remote. If they can see it’s you, they’ll just do the bad behavior when you aren’t there. Interestingly enough, the one I brought inside will perch on my arm and follow me around, and as soon as it came in, she never even looked at it. I think it’s that the dogs seem to almost know chickens are food, but if they see you treat them like pets (as good as they get sometimes) they are more likely to leave them alone. Now I just have to make sure the dog knows she can chase birds, just not mine!