Love the dog. Is he/she an outdoor night watchman too or indoors at night? He/she would make a good match for day/night predators.
Raccoons, opossums, stray cats, rats, even hungry mischievous stray dogs are night predators and are never where you can see them and roosting hens will be too sleepy to notice anything to sound an alarm before it's too late.
We didn't have Raccoons noticed in our city neighborhood until about 15 years living here when we happened to catch one scurrying down a sidewalk storm drain before our car almost hit it at about 2 a.m. Thing was as big as a goat! Ask around your neighbors what they've seen in their yards or streets at various times of the day/night. We talked to about 6 neighbors before someone actually confirmed info about seeing raccoons. We've seen dead opossums hit by cars occasionally on our suburban city street. A lot of birds of prey, skunks, opossums, and rodent-type animals live in the brush or trees along freeways, highways, and parks and many don't come out until dark. You'll never see them coming. Talk it up with your neighbors. That's how I discovered there was a resident Cooper's Hawk in the neighborhood and why we set up numerous low lean-to's for our free-range yard chickens.
Ah she comes in at night. Hoping her scent keeps the raccoons away. But if not, they get locked up tight at night, and I even put a brick in front of their coop door.