When it comes to dogs who are, or are not, good with chickens it is a case by case, or dog by dog, basis. There is no way to tell if any particular dog will be good with chickens until it see's them for the first time and you can observe it's response. A person who knows dogs can often tell by the initial reaction whether that dog is trainable to be a good farm dog or not. And no, not every dog can be taught to be good with chickens, some just do not have the temperament for it.
I have raised and trained my own ranch dogs for years and I consider every new dog or pup a predator until it has had sufficient, and by that I mean actual years, of training. I do not allow pups or dogs to have unsupervised access to chicks or chickens until the dog is fully trained, period. Once a dog has had the experience of chasing down, playing with and perhaps even killing a chicken it just sets your training that much farther back. My pups go to the barn with me and are in amongst the chickens every day as they grow up but they are leashed to me and under control at all times. Easy to nip bad behavior in the bud. None of my dogs have ever killed a chicken.
It also has little to do with breed. While some breeds are naturally easier to train and to have around livestock there are shining examples in most breeds of good and bad farm dogs. Temperament and training are key, you need to be prepared to spend a lot of time training any new dog or pup. So many, many people simply bring home a new pup or dog and turn it loose with access to chickens and then get mad when the dog kills them. That is called setting a dog up for an epic fail and it's not fair to the dog. The time spent training is well worth the effort in the end.
Owning both dogs and chickens is not hard, but you do need to be willing and able to invest the time needed to turn out a good dog.
