When we started losing chickens to hawks a few months ago, I looked into getting something to act as a guardian for the chickens. Geese, turkeys, donkeys, llamas, and dogs.
We finally settled on a pair of young Great Pyrenees. They're brother and sister, and came from a line of working dogs. In their first home, they lived with four adult Pyrs among sheep, goats, and chickens. They didn't have any fancy papers, and cost us $50 each. We've had them almost 6 weeks now, and haven't lost a single chicken. I've watched them run off numerous hawks (including trying to leap up and catch one flying overhead), three dogs, and either a raccoon or possum (too dark to tell which). They confront strangers who go to the chicken yard without me or my wife. Even though they still play with each other a lot, they stop regularly and scan the perimeter of the fence.
After seeing how they behave at 6 months, I can't fathom how good they'll be when they mature and "get serious" about protecting the flock several months from now.
If there's any downside to these pups, it's that they occasionally (maybe a couple of times a week that I see) try to play with the chickens. They've never hurt one, or tried to, but they do sometimes chase them. I think the chicken is more in danger of hurting itself trying to get away than from the dogs. A yell from me stops the dogs cold, and changes their attention.
Oh, and they like eggs, but I've about got that taken care of.
