I'm in the process of building my coop and my plan is to also make a fenced in run for them to use while I'm at work, and they can free range on the weekends when I'm home. When building the run, taking into consideration that they will be locked in the coop during the night, do I need to put a top on it? Or is there a height that I should build the fencing so that daytime predators won't climb in? I think the only daytime predators I've seen around would be a couple stray cats. I know that we also have racoons and possums, but I haven't seen them during the daylight hours. TIA!