I'm not sure if I should call it free range or a run, but basically I want to contain about 20 birds in some form. A little about the property...I have 2.5 acres and half of it (the back and 1 side) is a creek that's about 20-30 ft wide and 1-4 deep. The birds will be in a converted two stall barn that is prob 15 yards or so from the creek. I want to fence off an area for the chicks to be able to have fun, but keep them safe. I'm worried about a good chunk of the yard bc it's open pasture and we have plenty of hawks (land behind me is woods and nature trails). I've been told by the boss of the house that I have a spending limit with the chicks so if I could use the creek as a boundary, it would allow me to give them a much bigger area w/o spending so much on fencing. Can I use the creek? There are big dogs in the yard so I don't worry about any 4 legged friends coming through the creek (only otters maybe). Also, I'm considering field fence to keep them in. Their coop will be very secure so i don't intend this to keep night predators out of the run. Is that my best best?