Their run is covered on top with metal sheets. We put heavy plastic on 3 sides to keep the rain and snow out this winter, but allow sun in and have the greenhouse effect but also have plenty of ventilation. Last night we had a severe wind advisory here in SD (60mph winds) and it ripped all the plastic sheeting off. I'd like to not use that again and use something else that would handle these winds.. I would want it off during summer.