I can only tell you that if you choose a LGD, you may lose it to the neighbors flock of sheep. These dogs will guard chickens, but they have such a strong guarding instinct, they seem to gravitate to sheep and goats over chickens. Unless your fence is really good, you may just find your dog guarding his sheep!
Now, you may not have this happen either, I just wanted you to be aware of it. A lot depends on training.
I have a Blue Heeler/Border Collie mix that guards and protects the chickens. I leave her in the run and leave the coop door open. She has raised litters of puppies with my chickens. She accepted the chickens very easily, and I could leave her in a pen with day old chicks and trust her not to hurt them. Her greatest trait is that she is a natural mother. She will mother anything...she has let goat kids nurse her, and she loves the pot belly pig babies too. She hates cats, but will take care of kittens. She has brought me newborn baby rabbits that had fallen out of the cages, unharmed, and will show me where she found them, so I can put them back with the right mother.
I have had one Great Pyrenees that killed chickens if they went into the pasture with "her" goats. She has been the only one I've had that would do this, though. Even her pups didn't go after the chickens.
I recently gave a Red Heeler away to a friend, that said he must have learned a lot from my Great Pyrenees cause he won't leave their pasture of horses except to eat. He doesn't bother their chickens either.
I've had Doxie's, Rott's, Heeler's, GP's, & a Boston Terrier that were all good with the chickens. I really love my GP's, but there are so many dogs that would work.
You might be able to do a test trial period with a dog, before buying it. I would ask the person who is selling about that. Most responsible breeders will want to make a good match for their dogs in a new home. I'm not a breeder by any means, but I have taken a dog back that didn't work out for the people who bought it.
I probably haven't helped you much, but maybe I've given you a couple of ideas.
Jean