I am building the Taj Mahal of chicken coops. The run is 24 feet X 18". I want to put something over the top to protect them from owls and hawks. Will landscape fabric allow enough rain to come through that it won't collapse the walls? I am trying to keep from building a frame, because this project has taken way too long. I know that a tarp will just allow it to puddle and then will collapse. Any suggestions are appreciated.