I always have more than one big guard dog, currently two Akitas and one Chow Chow, excellent natural guards for the experienced dog owner (not recommended for the first time dog owner or those who have a hard time getting Shepherds, a much easier breed to train, to obey). Multiple dogs, I think, are more of a disuassion than one. One can be easily dispatched, two or three, not so easy.
I know how heartbreaking it is when dogs lose their lives doing their duty. I had several things "walk away" off my property before I had dogs, then I adopted an adult Pit Bull/Lab mix and also acquired the Chow Chow I currently have as a pup. It turned out, it would seem, that the thief was my next door neighbor.
My neighbor hated the Pit mix and the feeling seemed to be mutual with the dog when he was normally friendly with everyone. That was the first hint that it was my neighbor. The Chow was a young and "stupid" puppy and didn't seem to care, would bark at my neighbor along with the Pit mix just for the fun of barking.
Then when we went on a week vacation and had a trusted caretaker come in to take care of our livestock and dogs. A few days later he called to tell me that the dogs were gone. The following day he called and apologized, but said he thought it was our next door neighbor who did something to the dogs. That was the second hint that it was our neighbor.
When we returned home, the Chow pup showed up and was still wearing her collar/tag, but the Pit mix never returned. I went to the pound every day looking for him. Then about a month later I get a call from a woman saying she found my dog's collar/tag in her backyard. I asked where she lived...turned out she was my next door neighbor's wife whom I rarely saw other than driving down the road to and from the house, I assume, to work and back. We had never really spoken before and she didn't realize who I was at first. I walked next door and met her, she handed me my dog's collar and tag and had a white as a ghost, horrified look to her like she was realizing what had happened to my dog. She was overly apologetic, way too much so, for someone just returning a collar.
That was when it was confirmed in my mind that it was my neighbor, but I had no proof.
Since the Chow Chow was now a single dog and even though she was starting to become more mature and protective, I decided to get multiple dogs. I acquired the two Akitas and thoroughly socialized and obedience trained them.
After that I have always had a minimum of three big dogs. I have since never had anyone mess with them, nor successfully enter my home (I had one attempt, they apparently never got passed the back door through which they attempted to enter).
The Akitas are the best guard dogs I have ever had, they have the natural instinct to "hold" intruders which is bred into them. And they are a naturally quiet breed, so when they do bark, you know something is amiss. Without training, they will encircle intruder(s) and stand a distance away and stare at them and bark aggressively until they stand still, then they will stand calmly and bark rhythmically until we come out or the intruder(s) attempt to move again, to which they will advance and bark aggressively again until they stand still.
I've actually watched the Akitas do it out my window when some friends came strolling onto our property not expecting that sort of reception, lol. I was frantically trying to get dressed since I had been in the shower when I heard the dogs start barking. They never touched my friends, but made it quite clear that they meant business. They also are naturally quiet and quite aloof/stay out of the way when I'm around when strangers come in. They seem to naturally understand that they are not required if I'm meeting the strangers myself.