We have corgis. They are livestock herding dogs. As was mentioned above, and with which I completely agree, our dogs were given limited access and then commands so they know what to expect (they were previously trained to follow our commands as they are 10 and 13 years old). Corgis though, particularly the females, can be aggressive with other animals especially those bigger/taller than they so if you are not the trainer type (the training is more for the owner than the dog so any owner needs to be willing to do the work), I'd leave most dogs alone. We do rescue and we get far too many requests from people who chose a dog, even the right dog, but then things didn't work out when the dog wasn't perfect and they get dumped. Every dog has pros and cons, and you should research those before buying. I can see big, lumbering dogs being good for chickens (like that Bouvier mentioned above). They tend to be kind, patient, watchful (more than reactive) dogs. Bernese Mountain dogs, English Sheep dogs, and St Bernard's may work well with poultry, but they are big, eat a ton, and may have time consuming grooming requirements. No dog is a win-win (not generically, at the breed level). Take a year or so. Talk to breeders. Research the breeds. Find the fit that works best with your life and expectations. Chances are if the dog is good fit for you, you'll guide him/her into being a good fit for your flock. Good luck.