There's been a security breech in the chicken run but we can't figure out what kind of varmit it is because we don't see tracks or scat in the sand. We had taken extra precautions when building the coop, like burying construction wire underneath and the sides of the coops and putting an outside perimeter fence around the coop to keep dogs out, but somehow a critter has found a weak spot. We lock the girls in their coop every evening, and we don't leave food or water in the run. I have attached a photo for you to see the size of the hole. No matter how much we cover it up, block off the entrance from the outside with large rocks, or lay stick traps or rat traps along the edges of the coop and inside the run at night, the critter continues to burrow in every night for the past four nights. We crept out in the wee hours and scared whatever it was out of the burrow and it knocked over a trap but wasn't caught. Rat? Weasel? I'm about to open up a big can of whoop arse! Any advice is appreciated!