[header] How to train dogs to leave chickens alone [title] Spend time with the dog outside. [step] As the two of you are outdoors together, aim to get close to the chickens. Introduce the dog to the chickens only when the dog is on a leash. 
It's a good idea to sit near or among the chickens, talking to them gently and to the dog gently too, keeping everything as calm as possible. If the dog can see that you care about the chickens and treat them as important, it may realize that the chickens are off bounds.