I have a heeler and a standard poodle. No chickens presently. The heeler was around chickens from a puppy, the poodle was about 4 when introduced. The heeler wanted to herd the chickens(make them run), the poodle would put her foot on their back and lick them. Neither ever killed one, and the chickens would snatch dog food out of their dishes when the dogs were eating.
Now the neighbor used to have a german shepherd and a mastiff which would sneak over and kill my chickens, grrrrr.
Personally I think it comes down to teaching the dog NO, and that YOU are the master/pack leader--the dog obeys you. They must be supervised, cuz they are dogs after all. My poodle I would trust with chickens(we once found her locked up in the coop for the day with the chickens, no casualties), the heeler not so much because she would chase them to exhaustion if left to her own devices for a long time(not neccessarily to kill, kwim?). The chicken coop/fenced chicken yard was OFF LIMITS to the dogs, they were taught they weren't allowed to go in there(ha, despite the poodle getting locked in there, that was freak...stuff happens with kids around I guess
Just saying with me it was a question of does the dog repect me--it HAS worked with the two dogs I have(actually I had another heeler that never killed/chased chickens either, so three dogs). The chickens are MINE and the dogs can't have them, just like my food on my plate is MINE and the dogs can't have it(and woe unto them if they try to steal some). I know different breeds will act in different ways, and you have to work with it.
Hope that helps, ya gotta have the training first though, before the chickens, so the dog listens to YOU.