Right now I have all three ducklings (Cayuga) in our garden tub, but I will be moving them outside sometime this week. We are using an old shipping crate for their coop. It's a pretty large box, so once they get bigger they will move onto the covered run. Any suggestions on how big the run should be? I have a spot picked out but I'm not sure exactly how big I'm going to make the run. Another thing...I have a fear of foxes, dogs, coons, etc. digging under the pen, any ideas to stop that?