I recently added two cyclone fence kennels to my run for added space. I tied down 10 foot metal poles across the top, then covered it with hardware cloth and secured the cloth with hog clips. The weather will go through the cloth.
DO NOT USE A TARP...I did that on my first run and it was a pain. The rain collected, the snow collected and we had to lift the tarp everytime we went out there to get the water off of it and it made the tarp hold water and swell down into the coop.
I also suggest you cover your chicken wire with hardware cloth...up the sides from the ground three feet to keep predators out. Chicken wire holds chickens in, not predators from getting in. Great looking coop and run!!!!!