Raccoons often forage in family groups. While one member of the family group flushes the hens to the far side of the pen, one of the other coons will be waiting. When a hen comes into range the coon will stick its arm through the wire and grasp the victim. Then it pulls the hen up against the wire where the coon will eat everything it can get its mouth on. Since a coon's foot or "hand" can grasp a chickens' necks better than it can a chickens' body, the neck will often be the only part eaten and the coon never enters the pen to kill your birds, the coon just eats your hens necks through the wire like you or I eat an ear of corn on the cob.