I am one of the few in this thread who seem to trust their dog with their birds. I got my chickens four years ago (have had 50 or so on the yard since then and
not because they were killed by him-they were sold) and I brought the birds home and put them out on the yard. I have a Border Collie/Heeler mix and first thing he wanted to do was of course check them out. I had them all in individual drop pens so he could see all of them from every angle. When his ears went up when one spooked I gave him a "No! Leave It!" and that was it. He loves his chickens. Every day they get turned out to do whatever they want and we leave the dog out back unattended. We have three cats too that also sun bathe with the chickens and sleep on, in, under and next to their cages. It's the stray cats that are coming in that try to attack them, which is why we let the dog handle that part.
He has that protective watchful flock dog personality and will search the perimeter, sniff around, look and sit in the middle of the yard where all the ones out are and just watch around the yard. He even eats the chicken feed with them
which makes me mad and I end up huffing at him "Who's paying for the feed?! Get your own!" He calmly licks it all up as they're pecking around him. The only time they may get a scratch from him is if a cat or something has been in the yard that should have been and he flies out the door and the chickens don't move fast enough. They're under foot alllll the time. I've almost made friends with cages and the ground from mom's Cornish hen.
The other day a new rooster escaped who is terribly wild and we had to catch him quick. I called the dog on him to get the rooster and my dad and I did the blocking while the dog did the driving (no crazy heeler chasing, no BC eye or stalking) he follows intently and knows which way we need him to drive. We got the rooster against the fence and he got away from us and the dog took him over to the porch where the back door was open and stopped and let the rooster go in the house. Perfect!
We laughed and went inside. He flew up on the table and I got him. I weekly out of nowhere ask the dog to follow a bird for me I randomly pick when he's minding his own business and he will. If the roosters also get into fights he goes over and whines or barks at them. Then standing back a ways (he's been attacked plenty of times lol) he sticks a paw out slowly and tries to break it up. It's funny to watch because they either break up and turn on him
Only you know your dogs and what they are going to do, but I can understand why some people would not trust their dogs for so many reasons because some will turn on them first second you're gone.