We built some not too long ago and i highly recommend it. I was probably a little bit excessive but everything I do is overkill we ran 7/16" rope through a 3" PVC pipe every 2" along the top and let 18"-24" rope hanging down. We just made a eye loop at the end of the rope with a small piece of wire and a hook with the other end and it was quick and easy to build. We filled with Mineral Oil, Bifen and Perm-X 31-66 at the same ratios we fog with. We've only got 6 acres in pens at the moment, have dozens of fly traps and fog our pens every time we go around them as well as a perimeter a minimum 200 yds from the pens and still had flys on our deer's backs until we put them up. Our oldest doe walked right under the one between the doe pens within minutes. The gap between buck pens is 9' so I didn't bother hanging it up as Bell suggested and lowering it down but if you can it is a good idea. We let does into the alley to walk past and the bucks followed them right under it the first day but after we closed their gates back the yearling bucks avoided it for a few days.