I raise heritage breed turkeys and wanted a lightweight, mobile pen for them. I started by constructing an 8x8 frame frame using 2x4's.

Next, I made two door frames out of lighter 2x3's and then used one to connect the door frames and also provide support for the wire mesh. I used 5' by 50' welded fencing for the top of the coop and regular chicken wire for the ends. Everything was secured to the frame with heavy duty galvanized staples. I then used zip ties to link all of the wire. The doors were constructed from the wood of an old shipping pallet. (Not pretty, but it works!)

This is a view of how I secured the wire with the zip ties.

This is the (mostly) completed mobile coop. I just need to add some poultry wire around the bottoms to prevent predators from digging underneath. Otherwise the pen is very strong and secure. Now I just need to move it out to pasture and add the birds!