Do the coop walls need to be wood?

[Peep Nerd]

I'm thinking about rebuilding my coop and wondering if I need to make all of the walls wood. Could I build almost a hoop house style and cover it with a tarp? I'm in Maryland so we do have cold winters but the cold doesn't seem to be a factor for the hens. My current coop is plywood but I'm wondering how much that really insulates it. I also usually put hay bales along the walls. That keeps it pretty warm. As long as it's dry and safe, do you think horse fencing and tarp is enough protection?

 

[Percheron chick]

A dog and any night time predator could rip through a tarp. Is that a concern? I would always overbuild than underbuild. A well build coop is going to last for years while a hoop house might collapse with a good snow.