My husband used half of cattle panels to make these. Wiring was often recycled. Bottom wood frame was recycled. Still working on doors that "fit" tighter ..... Having these during a recent heat wave were so helpful as we quickly moved them under trees in the front yard. Literally a life saver.
We have reclaimed insulation panels which were added to protect in the colder weather. We also use use feed bags as a buffer against windy weather, especially in the winter. Hens tend to make their nest in the corners, so that's the area we straw. We did learn to use the best tarps possible as they last longer and ultimately cost less in the long run. Perches are placed in the corners as needed.
What I love about this is the portability, the height, the ability to repurpose materials. I can get inside the pen and chat with the silkies or other birds. Or do wellness checks etc or just to bring treats.