there goes my rem sleep.
For the first 2 years in my house, the next-door neighbor kept her dog outside all night, every night - sweltering hot, freezing cold, or in between. The dog was in a fenced area directly across from my bedroom window and our side yards are only 7 feet wide on those sides.
There are woods behind us, and although you don't see them during the day there are certainly numerous small mammals wandering around at night - raccoons, opossums, rabbits, groundhogs, who knows? I suspect that they realize that they can parade around just outside the fence line (my yard!) mess with the dog's mind.
Fortunately they moved away a couple of years ago and now a woman lives there with a small dog who stays inside at night.