We've seen hawks circle around way up high for the past two years we've lived here. So we built the coop and run accordingly. My son and I just finished putting up the bird netting on top of the run yesterday at noon. The chickens are thrilled to have all the space. Today, at noon, I was out working on the bachelor coop and here come two HUGE hawks way down low enough to say "Pardon us, we'd like to make a dinner reservation." So for those of you wondering about whether or not you need something on top of your run... it depends on if you want to keep your chickens longer than 24 hours! I'm starting to worry we should have put up something even stronger.