Training, training, and more training. A harness works better than a collar for this type of training because it gives you control of the shoulders. Also, people pay me to train their dogs (train the human).
If you know what a clicker is, use it.
First train "leave it". That means don't touch that thing. Start with dog on 6 foot leash, walk by something interesting, say "leave it" and walk away from them bait. but do it by walking directly away so that you are pulling the puppy in a different direction, different from your walk. Have treat in hand. As soon as the puppy turns from the bait, (click) praise and give treat. Repeat, repeat, repeat.
Play the game in the house. Use a toy as bait. Use the dinner dish as bait. When the puppy always leaves the bait alone go outside with longer leash, 20 feet. You need to keep collecting the leash in your hand and letting go depending on how close you are to the dog. Don't let her pull. When she comes to the end of the leash and keeps going, change the direction of the walk so that she is being pulled and has to follow you. When she understands that she only has twenty feet, walk by the bait. Have the leash up in your hands so you can pull her away if need be. Praise and treat.
At some point you start omitting the treat and just using praise. Usually, we would now let her get the bait every so often, but since she will never be allowed to get the chickens, you might want to not do that.
When you feel she is reliable, use a chicken as bait, making sure you can pull her off instantly if she disobeys. Repeat with the chickens over and over using a really good treat.