I'm sorry, but free-range does not mean someone else's chickens free-ranging on my property. As a chicken owner, I can tell you from experience that chickens can destroy a garden, not only with their eating, but with their digging & scratching. And chickens don't learn from scare tactics. When I allow mine to roam my garden area, I use a hose & a stream of water to get them out of certain beds. 5 minutes later, they're right back in the same bed. 1 of my chickens escaped and got into a neighbor's yard a few weeks ago. Dug up all the newly planted pansies. I had to spend $20 on another flat of pansies, $10 for additional mulch, and 2 hours redoing her flower bed.
If your neighbor had a large, vicious dog running around your yard, would you put up with that?
It's an owner's responsibility to care for their animals. Chickens, or any animal, running free through a neighborhood is not caring for them. Suppose they get hit by a car, or a predator, dog or cat, decides to kill them.