While raising backyard poultry predator protection is an essential component to your housing plans. When you are utilizing a free range poultry production method the threat is high as the birds get to enjoy the grubs, fresh air, and grasses, also predators get to enjoy your poultry. The highest risk is at night when many of the predators are hunting.
Generally the smaller the bird, the more likely it is to be a target from predators. For example turkeys are not as much of a target as chickens.
Poultry predators include coyotes, opossum, raccoons, snakes, rodents, hawks, eagles, owls, weasels, mink, fox, skunks, and dogs and cats.
If your entire bird is missing that can be a sign that either the bird was stolen by a human, coyote, fox, dog, or bird of prey. Owls will come at night and a hawk will hunt during the day.
If your bird is missing its head, the predator is most likely a bird of prey or a raccoon.
If your bird is missing legs or wings, the culprit is most likely a raccoon.
If you are missing eggs and chicks, most likely the culprit is a opossum, skunk, snake, or cat.
If your bird has cuts near its vent (butt), it is most likely a weasel because they kill for fun.
Suggestions for your pen construction: The easiest way to prevent predators is to have your birds locked up. But most people are not looking for that, we want our poultry out in nature. I might suggest motion sensor lights near the buildings as the predators generally fear a sudden new light. Scarecrows, diversion feeding, flags and pinwheels can detract predators as well.