Please forgive me if this has been asked before, but I have searched and haven't found the answer. I have seen on numerous threads that hardware cloth should be added to windows or to the bottom of the chicken run etc.... What exactly is hardware cloth? I have 3 windows in my chicken coup that have screens on them. We used 1 in. chicken wire around our run. I realize that the screens are not safe on the windows, so I would like some information on hardware cloth. Thanks for your help!