An LGD (livestock guardian dog) breed would be best probably but while they have protective instincts they MUST be trained to protect poultry. For instance, our Anatolian. Duke is his name. He would be very protective of the birds if he had been trained to be. As it is he spent his first year caged and mistreated until being rescued by our Vet. We took him in and he has shown his true protective and affectionate nature toward us and our other dogs, even to a degree the birds, but to have been properly trained he would have needed to be raised with the birds and live with them full time, not in the house with us. He has caught a couple of raccoons that came on the property and the results have not been pretty. But, he was following his instinct to protect his home. However we would not let him with our birds because he has not been trained to be with them.
We have, besides our chickens ducks and geese, hundreds of wild birds that we feed. Everything from doves to starlings to Purple Martins and sparrows. The dogs just ignore them completely. But if a hawk, buzzard, vulture or eagle come over the property our Boxer/Bulls (BT and Sara) go ballistic and run and jump to ward them off. So, with their ability to determine what is a harmless bird and what is a predator can we trust them alone with the poultry? We have not tried and probably will not.
Look into LGD's...especially the Kangal breed. If you got a pup and raised and trained it you might have success. I know there are plenty of pictures here on BYC of dogs with birds, do a little checking and see what breeds and what amount of training those members have. I am sure they will be more helpful than I.