I don't believe it's luck, as a man of science and realism. I believe your neighbors in their apparently horrible planning are paying the wildlife tax in your area and the use of what I presume is cattle stock fencing (?) keeping those baddies at a distance. Predators are going back there over and over because it's easy, why would they bother with something they'd have to actually conceive a plan for? I'll never fully understand the human condition in regard to predator proofings, in my most humble opinion it's probably the easiest part of raising fowl of any type. There may come a day when they do get it together and you may end up paying that tax after all.