So in the spirit of
permaculture, let me theorize a bit on natural order/food webby stuff.
Predators generally predate the introduction of domesticated poultry to North American by the European colonists. Naturally occuring wildlife species therefore, are the natural and instinctual prey for those animals we now struggle at times to out-fox (pun intended.) The exception to this is the domestic canines (the few
indigenous breeds of dogs tend to be small and rather terrified of
chickens... or at least my wife's Chihuahuas are.) Manmade or inflluenced gaps in their prey cycle (think of it like the daily special cycle at a restaurant) forces the predators to adapt. For example, in my area, indigenous upland game birds are almost completely vanished, leaving only pheasant. If June is "Eat Feathery Things Month," and they can't find the quail, grouse, & prairie
chickens their ancestors ate, they are going to hunt for other appropriately sized birds. Once the pheasant (in my area) start hatching out the pressure on my birds from indigenous predators decreases.
The wrench in this particular set of gears is domesticated predator species. The majority of medium to large size dog breeds have been selected and refined for specific behaviors. LGDs, I'm sure, we're all familiar with. Herding dogs who traditionally nip and bite to gain compliance work great to move
cattle and sheep, but when a 60# dog tries to bite a chicken to gain compliance, problems insue. Hunting dogs can be a real issue because their instinct is to kill. Add in a feral or perpetually stray dog, and you increase problems because hunger is a motivator. My first attempts with ducks ended badly because of a pair of dogs that were running loose. They also took down a couple calves.
Raptors are a completely different set of problems, but identifying their kills shouldn't be difficult. They tend to avoid carrying their prey far to consume them. Our last raptor kill was found less than 200 feet from the chicken coop at the base of a utility pole. The raptor grabbed it, carried it to a convenient spot away from competition, and ate his meal. Owls, incidentally, are excessively clever. A friend lost a several birds over the course of a couple weeks because the
owl figured out how to go through the chicken door (which was raised high enough to prevent land-based predators.)
Overall, with no feathers and no carcass, at this time of year when
rabbits, squirrels, and other rodents are in abundance, I'd lean towards a stray dog in your particular case, particularly given it sounds like a mid-day strike, while fox & coyotes prefer early morning and late evening to hunt.