I found this on the Chicken Run Rescue site. I don't think it's copywrited info but am attributing it anyway. I didn't think about raccoons being territorial this way.
"RACCOONS
Raccoons, the most prevalent potential chicken predators in Minnesota, mostly climb and aren't big diggers, but they can and do dig. Even with predator proofing they will try repeatedly to gain access; however, at some point instinct kicks in and tells them they are expending more calories than they might gain from getting a chicken, so they give up. Having a frustrated raccoon around is better than having eager, inexperienced raccoons. Raccoons are territorial, and once a raccoon has learned that he cannot gain access to the chickens he will focus on other prey (rodents, insects, snakes, frogs, eggs, etc.) and protect his territory from other raccoons. When this raccoon dies or is live trapped, a new raccoon will move into the abandoned territory and begin to test all the fencing and predator proofing, hopefully getting frustrated and abandoning that endeavor. However, if raccoons are constantly being removed (live trapped, killed) new ones will constantly be moving in and testing the fencing, and eventually one might get through. Better to keep that old frustrated raccoon around.
If perimeter fencing is used, all overhanging tree branches that can serve as a bridge for raccoons to go over the fence must be trimmed. The best anti-raccoon device is an electric fence. An electric fence requires an electric fencing low-impedance charger (solar powered ones are also available), electric conductive wire, four or more ground rods, and vinyl stakes. The electric wire must be positioned eight inches above the ground and eight inches from the fence on the outside of the fence (no point in shocking the chickens!). This ensures that the raccoon will get shocked if he tries to go over the wire to climb the fence or under the wire to dig."
"RACCOONS
Raccoons, the most prevalent potential chicken predators in Minnesota, mostly climb and aren't big diggers, but they can and do dig. Even with predator proofing they will try repeatedly to gain access; however, at some point instinct kicks in and tells them they are expending more calories than they might gain from getting a chicken, so they give up. Having a frustrated raccoon around is better than having eager, inexperienced raccoons. Raccoons are territorial, and once a raccoon has learned that he cannot gain access to the chickens he will focus on other prey (rodents, insects, snakes, frogs, eggs, etc.) and protect his territory from other raccoons. When this raccoon dies or is live trapped, a new raccoon will move into the abandoned territory and begin to test all the fencing and predator proofing, hopefully getting frustrated and abandoning that endeavor. However, if raccoons are constantly being removed (live trapped, killed) new ones will constantly be moving in and testing the fencing, and eventually one might get through. Better to keep that old frustrated raccoon around.
If perimeter fencing is used, all overhanging tree branches that can serve as a bridge for raccoons to go over the fence must be trimmed. The best anti-raccoon device is an electric fence. An electric fence requires an electric fencing low-impedance charger (solar powered ones are also available), electric conductive wire, four or more ground rods, and vinyl stakes. The electric wire must be positioned eight inches above the ground and eight inches from the fence on the outside of the fence (no point in shocking the chickens!). This ensures that the raccoon will get shocked if he tries to go over the wire to climb the fence or under the wire to dig."
