Ridiculous! I'll say it again, because it bears repeating, bird/hunting dogs are the EASIEST to train to leave chickens alone, and if you think about it for one hot second, it's obvious why.
These dogs were bred to focus ALL of their attention on ONE kind of bird. What good is a hunting dog that goes tearing off brainlessly over everything with feathers?? Less than none! In fact, you can't hunt at all with a dog like that.
Therefore, hunting breeds were specifically bred to be easily trained to hunt this and not that. So all you have to do is give the dog a this - which can be anything from the bluejays at your bird feeder to a tennis ball to the kid's socks - and train that the chickens are not that.
Now, keep in mind that I don't find hunting breeds particularly easy to train overall. I am a herding breed person, myself, with terriers as a close second. I just get on with them better in general. But I have yet to meet a single hunting breed dog, from hounds to retrievers, that didn't instantly catch on to the concept of this=good, that=bad. I can train three of them to not chase chickens in the time it would take me to introduce the concept to a companion breed.