We hatched 10 chickens...8 ended up being roosters. So after the roosters went to their new home I took the kids chicken shopping. Which of course resulted in 11 new chickens and 5 ducks. I have no will power! Technically the coop and run are of adequate size. But I'd like to make a larger duck pond. The problem is the area I want the duck pond is about 20' from the current run. I want to make a second run essentially and connect the two so there's a dryer run and a (likely) wetter run. What's the best way to make a predator proof tunnel?