Our chicken coop which is locked up every night with doors shut opens into large covered runs. We can open the run doors and they can free range within a fenced in area, lots of trees and shrubs. A few days ago I noticed a dug area inside one of the runs and thought the chickens were scratching for dust baths. Yesterday there was a round hole about six inches in diameter inside the run and the opening was outside so something had tunneled in. The hole in the run was about 6" in diameter, which seems large to me. I think it is something after the chickens. My husband thought it might be something after the chicken feed. The chicken feeders, located in the runs, are taken in at night but some of the feed is spilled on the ground. We and dogs are in and out often during the day and have seen nothing. Would a raccoon or opossum dig like that? A fox? My husband filled the hole with rocks covering the mouth with a large rock. He's thinking if he sees any more activity he will set a trap within the runs at night while the chickens are locked up. Any idea what could be doing this and if we set a trap what would be the best bait for an unknown?