I have a fence but it is to keep my dogs in. Four dogs, two Pugs and a Chihuahua, and a four month old Boston-Rat Terrier mix in training to be more of a 'farm' dog than the others are. My land is small and completely fenced...80 x 100 feet...but it is surrounded by thousands of acres of woods with few neighbors. I let my chickens roam in those woods, but the dogs are never allowed off the property. The chickens have a coop and roost in it at night. If one comes up missing and ended up in someone's pot for Sunday dinner, then it is my fault for letting them roam.
No fence will keep a determined big dog out. OK, maybe a fence like prisons use, but all fencing is expensive. It is not my responsibility to build a fence to keep other folks' dogs off my property. Large stray dogs will kill both my chickens, and my little dogs, and I'm an old lady...who is to say they won't attack me. Fortunately I've never seen anything but one stray dog and it was obviously a purebred mid-sized pet dog who had escaped from a nearby neighbor's where it belonged to guests. When shooed away, it ran for home like a streak.
After the big snake issue...another thread and story...I started carrying my .38 loaded with snakeshot around with me in the yard...it is always carried when I'm out of it. (legally, with a permit) It is not my job to train the folks that live around me how to manage their animals...including their dogs. As far as I'm concerned everyone should know that dogs that roam are not allowed. I've got sense enough not to shoot some pet that has escaped. I love dogs, I'll catch it if possible and make it my job to return it to it's owner. Unless it is threatening what is me or mine in which case I'll shoot it. My ammunition will not kill a big dog...and probably not a smaller one, but it will slow them down while I reload with ammunition that will. I don't want to shoot anything but I will if I have to. I've lived here a year and a half now without any stray dog issues so I'm lucky.
When I was a preschooler the family had a big black dog named Lincoln. My dad had been a MO farmer prior to joining the Navy submarine service to fight in WW2. Lincoln was never tied and roamed our 13 acres. Unfortunately he went onto a neighbor's property and got into their chickens. They told my dad...who took him out back somewhere and destroyed him. That was the first time I ever saw my dad cry and it made a big impression. Sixty years later I sill remember it like it was yesterday. The lesson that one is responsible for the actions of one's animals as well as their welfare was driven home.
It would be nice if we all had responsible neighbors who controlled their dogs but how far away from you can you expect that to be? If I live next door to someone who has a female in season...male dogs are going to come from miles around me. Should everyone neuter their dog? Probably, but I can't make them. I can afford to fence my little piece of the world, but some who live around me have hundreds of acres they own...most of it if it is fenced at all...is fenced by barbed wire which keeps no dogs in.
I can't control, and can hardly influence all the folks who have dogs that live within 'dog distance' of me. Although I live in a rural/farming area I cannot expect every single dog owner to be as responsible as my dad was. There are three kinds of stray dogs, those that are outside my property, and those on it, and those trying to get in. The last two groups get no second chances...the first group just gets watched. If they are going after my chickens in the woods then that is my problem. That's not my property. If I want to protect my chickens, then I better keep them on my own land.