Small Dog protection
"A lot can go wrong when a little dog is left alone outside" (Tufts "Your Dog", May 2022)
Wildlife such as coyotes, especially in the springtime, large raptors (more likely an attack by a raptor rather than being carried off), and other wildlife. . . are not the only reasons to be cautious. By the way, a dog door does not necessarily protect your dog from an attack as coyotes have been known to enter a dog door while in pursuit.
Walking a small dog on leash comes with thought, too; allowing your small dog to walk behind you, out of your sight while in an environment where other dogs may be present, could be an opportunity for another dog who is only curious, or more concerning, a dog who is suddenly aroused and experiencing predatory drift has taken a sudden interest in your fast moving little dog -- time is of the essence; a grab, shake and kill happens very quickly. Picking up your dog in this situation may not be enough.
There are still plenty of dogs out there who spend a great deal of time in their backyards unsupervised, routinely pursuing wildlife, and in some cases learning to hunt and kill small wildlife -- these are the dogs you want to use extreme caution around when you have a wee little dog. For this reason, I advise my clients (of the littles) to walk their dogs on leash with awareness, maintaining peripheral visual of their dog. Proactively slowing down and interrupting a fast-moving small dog can help reduce excitability in other nearby dogs.