
I think the trick to dogs and chickens is to introduce them early when the chicks don't know to be frightened (so they won't run and flap and excite the dog's prey drive), and then have lots of closely supervised interactions. Tell the dogs they're very good for being gentle. This way the dogs get the idea that the chickens are pets. This has worked well for me, but my experiences have been with herding mix dogs, who are predisposed to look after animals they think of as "theirs".