While labs may be more interested in the chickens than other breeds, they also should have soft mouths and be less likely to kill chickens (theoretically they should carry them without injuring them). That being said, each dog is an individual, and should be treated accordingly.
I've found that with my dogs, (2 pitbulls, with a 3rd foster pitbull) having excellent basic obedience skills makes it possible for us to all be out together. I can tell my dogs to stop, back up, walk away, come to me, get out of the situation, or down and stay. They look to me for guidance and have been very easy to teach good manners around the birds. If the birds scream and flap across the yard, my one dog with the highest prey drive, looks at me like "OMG can you believe they did that, and I can't chase them". On one of the first meetings the birds started flapping, she started chasing, had one bird 6 inches away from her mouth, I said "NO, OUT" she stopped dead in her tracks, took two steps back, and looked mournfully at the bird running off.
And for all of you that think harsh training methods are the only way, my dogs are trained with food rewards, clickers, positive reinforcement and time outs for bad behavior. They have never been physically corrected in their lives, no choke chains, no hitting/smacking, no shock collars, no poking and hissing in the cesar milan method. And they are pitbulls, dogs that many people think are uncontrollably dangerous.