Teaching my dog to not attack our small farm animals

You have to keep them separated, at least until your dog realizes eating the chickens is not good. However, this will be difficult since it's in a dog's nature to "hunt" food. If you can teach your dog that going near the ducks is not good (like making a loud sound when he goes near them to scare him), you may succeed at getting him to stop attacking them. I hope this helps. Good luck!

If your dog's breed naturally hunts birds, I agree you have to keep them separated.

If the breed is not a hunting dog, you can try, with complete supervision and keeping the bird safely caged, to bring one inside and teach your dog to stay away from the cage, much like you teach a dog to stay off the furniture. Once he gets that, he should relax around the bird and be curious to watch it.

If I could train two cats to not kill my birds, you can definitely train a dog to not harm your ducks and chickens.

It can also be dangerous to the dog to eat fowl, especially because they can choke on small bones so you minimally have to keep the dog away from your birds and keep his belly full with everything but chicken or duck based dog food or treats. If you feed him these flavors, he's not going to understand he shouldn't eat the ones not made for his own diet and treats. I changed my cats diets completely to fish, liver and beef products only and, with a little training, they stopped bothering my birds.

Hope this helps.