Opossums can be among the most annoying of chicken predators partly because they can squeeze through shockingly tight gaps and partly because they kill primarily for the fun of it. They usually attack at night, but in the winter hunger may embolden them to arrive in the daytime, as well. Opossums may kill as many chickens as they can get their teeth on unless interrupted or distracted by another food source, such as rodents, eggs, or perhaps even chicken feed. Once they find a way into your chicken housing, they will return to pillage every one to two nights. Sometimes they can later be found resting near the scene of the crime, perhaps even in a cozy nesting box.
A nighttime attack with multiple chickens found dead is a good indicator that an opossum is the problem. However, in some cases, only the chicken on the lowest perch will be pulled down and killed. Opossums can be somewhat sporadic in what they choose to eat, although they will frequently consume the head. They may also open the carcass from the back and remove the internal organs. Survivors may show bite marks on the breast or thighs.
The best defense against opossums is to protect the flock with electric poultry netting and to keep the voltage at a minimum of 4,000 volts. This implies that the fence must be kept on both day and night and that it must be kept free of grass and other debris. Also, as an extra line of defense, housing the chickens at night, preferably behind sturdy welded wire, is strongly recommended.
Raccoons are among the most intelligent of chicken predators, making them somewhat harder to thwart than others. They tend to travel in groups and at night, sometimes dawn or dusk. They use their nimble fingers to reach through chicken wire and grab their prey, or even to tear apart weak materials. Raccoons will only kill what they intend to eat, but because they do travel in families they may take more than one chicken at a time. Some raccoons, however, will leave the chickens alone and eat the eggs instead.
Raccoons are not terribly picky about what part of the chicken they eat. The evidence you are most likely to find will be a chicken partly pulled under or through the fence or housing and all accessible parts of the bird devoured. Wings, legs, and heads are most at risk. Should a raccoon manage to extract an entire chicken, how much it eats will depend on how hungry it is, but it will likely start with the head. Survivors may have deep scratches from grab attempts. Raccoons that eat eggs will usually leave the broken shells in or near the nest. Regardless of the dining preferences of your local raccoons, they will often cause structural damage such as stretched, bent, or torn wire, or possibly latches deftly undone. In some cases, you might also smell a faint musky odor.
Excluding raccoons is essentially the same as excluding opossums. Use electric poultry netting maintained at 4,000 volts or higher. Lock the chickens up at night, keeping in mind that welded wire is a much sturdier material than chicken wire. For an added layer of protection, secure the door with a clip.