I actually have two Australian Shepherds and one Blue Heeler/Border Collie mix who are great at protecting the birds. Granted, we have had them since they were puppies so they never had any issues learning to chase the birds. They patrol around our place really well, have killed lots and lots of coyotes, racoons, skunks, snakes, etc. I do think they work so well because we have three of them. Not sure one could take on a coyote since they are usually running in groups of three or more. The LGD are good too, Great Pyr are what my friends have but they are just bigger than what I would like and don't live as long, 7 yrs is an average lifespan for giant breeds. Just some thoughts. Good luck!
I second this! We have a Blue Heeler- Aussie Shepherd mix. It took us a year of work to get her trained well. But now she is the BEST thing to protect our birds. As long as it isn't raining she is sure to keep coons, fox, rats, etc at bay. I even trained her to chase off hawks and eagles. She is so eager to please. She will sit and watch the birds of HOURS!
The only habit that was hard to break was newborn ducklings. But gosh darn it, they just sound so much like a squeaky toy!!!