I have over the years used many breeds as free range poultry guarding dogs. None breed to purpose in respect to poultry. Not all poultry species same in respect to mobility and attractiveness to predators. With chickens I have had success with black and tan coonhounds, dalmations, border collies with present effort involving German short-hair pointer (bird hunting dog). Rearing dog with poultry helped a great deal although training needed with some and much of that had little do with immediate safety of chickens. My free range chickens do not move in cohesive group like ruminants (sheep, goats, cattle) and are subject to a broader range of predators. The smaller more active breeds have been my preference since they operate better when predator interests in flocks strongest (when predators raising young and it is hot). The larger LGD are like using a sledge hammer to tap in nails when largest predator is bobcat or coyote. My coyotes not those introgressed with wolves or domectic dogs so do waste time with that tangent. The larger LGD as previously mentioned more prone to heat stress and not as inclined to move about if multiple flocks are dispersed about property. Also in respect to dog roaming when off or on duty, I make certain neighbors know my dog(s), the dogs purpose, and that I value the dog highly. It is my responsibility to ensure my dog does not pose risk to valued possesions of neighbors. Not all dogs and neighbors compatible in that regard.
Dog breed will be a function of resources you have. If all birds in flock or dog confined by fence, then any breed will do but consider heat and cold stress in respect to dog size and coat type. If birds more spread then more mobile and possibly more dogs needed. If bigger predators, then bigger and or more dogs needed. With some situations the cost of using dogs is prohibitive, so keeping birds will need to be in smaller area that can be more readily fortified.
I restate, no breed of dog is bred to task of guarding poultry but probably all breeds have potential with good and bad individuals in all breeds. Being good with dogs will also effect outcome. If you can not control dogs, then I advise against using them. Most folks in my experience that have diffuculty with dogs and chickens are not skilled in keeping of former and should keep birds in coops or covered runs unless they are willing to sit with firearm all day and night.
