I live in New York state, 90 miles north of NYC.  Many of the property owners all around me are wealthy NYC people with weekend retreats.  I live on a dirt road.  People love the charm and the small town feel of our long 3 mile road.  Horses hack down the road, children run in their huge backyard fields, and we all have MANY varied types of  animals.  There is a huge pack of neighborhood dogs that roam all around.  If one neighbor said "keep your dog off my property" we all would be us the creek with out a paddle.  I have a LSGD that has a natural instinct to protect property, and rarely roams, even with being intact.  Unfortunetly, I also have a Cavalier King Charles Spaniel that  does act every bit of the country spaniel and roams off.  My LSGD feels compelled to "watch over her" and this is the only time he does leave. 
 
When we bought the place, and the nice neighbors brought a welcome pie or cookies to say hello, 5 of the people who owned dogs asked, "do you have a problem with our dogs crossing your property?"  Our response was..."Not at all, as long as they are nice dogs who don't attack or bite people, attack our dogs, chase my horses,, dig huge holes, or poop excessivly right outside my door."  In other words, if they are nice, safe dogs,, we love them.  If they are a problem, we have to talk.  I also informed them, if my dogs are doing any thing offensive if you see them on your property, here is my cell # and please call me, as I will do anything to rectify the problem.
 
Well, this worked well for about a year, then one my neighbors bought an Akita.  Well, the whole balance of the neighborhood pack got thrown out of whack.  By six months she was attacking and pining dogs for fun.  These dogs are bred for fighting,,and gaurdianship.  They are not social dogs, they attach to one person.  Now before all you Akita lovers out there attack me, I realize there are nice ones, but on the whole, these dogs are dominant, and especially when raised by people who don't know how to properly handle them, they often become the ALpha over human, and this is what happenend.  She attacked poor Harry, our neighbors 16 year old beagle who was deaf and on his way to blind.  $5,200 in vet bills later, Harry's owner reported her, and the dog warden got involved.  At least her owners did the right thing, got a dog trainer 3x a week, and put the invisible fence around their property and is only let out of her kennel run with supervision.  Well, even with all these precautions, Harry on New Years Eve made it at least to his owners deck and collapsed, attacked again, but this time he didn't make it.  The owners of the Akita, as nice people as they are, are in denial.  They insist it wasn't their dog, and refuse to acknowledge any responsibility.  Why do people own the type of dogs that they know are not meant for the outside world at large.  We all work together on this block, and we all are open minded.  Now we have hard feelings, and I sit and worry every time I go outside and Jack isn't within eyesight.  I leave him out all day when the chickens are free ranging.  I would hate to be told that I coudln't do that,, BUT HE DOESN"T ATTACK ANYONE OR THEIR PROPERTY. 
 
I am sure you would be fine with that lab on your property if he was a nice, friendly and watchful over your chickens.  I am sorry that your neighbor is in denial.  I pray no one, child or chicken get hurt by this dog.  Why can't people work together to solve problems. I would be the first one to keep Jack on property if I got a call he was being problematic.
 
Good Luck, keep us posted.
MB