Our town has a Family Farm and there are 2 Great Pyrenees who watch the flock and also the sheep... seems to work...
So that may be a posssibility as mentioned... a gentle Giant
But I have found a SMART dog is best. We have a med-sized mix
possibly an English Setter, Brittany, Husky, ??? but he's smart and likes to work.
He's really been a big help over the years with the horses and now that we have chickens for the last 2 years,
he's been great with them too(you CAN teach an old dog new tricks)..
He knows to gently chase the chickens to the safe side of the corral, and to leave them alone
when he is on their side of the corral or inside the barn, part of their domain.
Now the Blonde(Labradoodle, or something poodle)
did not get the Poddle brain, sadly, and is only OK if I'm near her..."Leave It" can be heard as soon as we get in the
barn...and she will, I can turn my back... but I don't trust her alone. Those squawking, running, feather fluffs are just too tempting..
And if you're starting with a puppy... well pros and cons to that.
Also...when you are looking, There are tests you can do with a puppy to test their smarts. Ask any trainer and they should be able to help.
Most of those "working" dogs, Hearing-Ear dogs for the Deaf... TV dogs, and even some Seeing Eye dogs for the Blind... started as pound puppies.
So you don't need some fancy papered dog. I'm not sure I'd trust someone I 'ordered' my dog from to pick my animal anyway
...just my opinion and with all the over breeding and such mutts are easy to find and healthier.
I think I'd look for a dog that is SMART, CALM and work with them ALL THE TIME. I still work with my 14 year old..'cause he's smart
and he gets bored if we're not doing something challenging... He's NOT calm, but he's trustworthy.
You'll find the right animal if you're patient and ask the universe... then check your pound!
Good Luck...