I found a dog that was and is bred for watching over chickens and other farm animals it is called a kangle look it up on yahoo or something I was very impressed with it and I'm looking in to getting two of them. Hope this helps
I live in an area that has a lot of predators-----fox, coyote, coons, oppossum, weasel.
I have not had any problem with any of them even going into the big pen (100' x 100') that surrounds my coop and 2 smaller pens-----I don't even have anything around the bottom of the pens/coop (like the hardware cloth).
I have a shepherd that is outside most of the year, but she does not go in the big pen----she would eat my chickens and ducks.
I think the fact that I have 6 goats and a barn-cat keeps the predators away----along with the scent of the dog. I don't know any other reason that a raccoon wouldn't at least go into the big pen and check things out.
We have a Maremma Sheepdog that lives with, eats with, sleeps with and guards the chickens all year round. I think he is a great breed. Other Livestock Guardian Dogs work well but after all the research I did, I considered Maremmas to be the best especially after learning about the success that wildlife conservationists had in guarding an endangered species of penguins from encroaching predators. They can also handle cold climates better than some other LGDs. But Maremmas need enough room for healthy exercise and MUST be fenced in.
With regard to WVman's post, a Kangal (or Anatolian Shepherd) is also a livestock guardian bred to guard sheep and are also known to do well with other livestock and people. My only apprehension with them for our particular situation would be that they are pretty big dogs that eat more and have a shorter lifespan. And they cannot tolerate the cold as well as a Maremma.
I have also heard the donkeys and alpacas work well, but those do not actively guard the way a Maremma or other LGD does.
We don't have the big predators, but we have opossums, raccoons, hawks, and stray cats. We have three goats that have a pen right up against the coop run, and we let our chickens free range with them. I will tell you that we have never had a problem with predators getting into the coop, and the goats will freak out if anything gets near them. Just this morning, all three of them went out in the pouring rain to chase away a group of wild turkeys that were passing through their pen.
My aunt has had her whole flock taken out by foxes, and she eventually had to pour a concrete floor and covered it with sand.