SF, my pens are simply constructed. The 4X5's are just made from 2X4's for the base and dog wire for the sides, door, and roof with a tin/tarp (or anything else solid) cover to block sun and rain. It makes the pens light weight and easily moveable to ensure the birds can remain on grass limiting their chances of getting worms as can happen on dirt floors as well as being healthier for them in my opinion. In times when grass grows slowly or is dead (I.e. during winter) I just rake leaves up and fill the pens unless someone has hay or other material free. For single birds, like say I have some spare cockerels I want to keep in pens, I have some round pens that are just solid dog wire. Basically speaking, many of my pens are what most would refer to as "Chicken tractors" minus the wheels and fancy nests a lot of them have. For nests, I use 2.5 gallon buckets that have had the tops cut open about half way to allow the hens to climb in but the eggs can't fall out. For larger birds, like the Shamo I've even used milk crates/old coolers that had no top with success.
The pens I have are old, they were built primarily by my grandfather/father probably I'd guess easily 20 years ago, maybe more. But, they still get the job done so I use them. Other pens we have in the barn and haven't been used in years (falling apart now) and is a common type of pen around here is a frame constructed of 2X4's that are 3' wide, 4' deep, and about 6' tall. The bottom half is covered with sheets of tin with the top half (door included) being made from wire. These were breeding pens as well, usually holding a pair or trio of birds. Haven't got photos, but hope by my description you can understand; I thought there was a thread on here already somewhere about pens. We've even had pens made out of pallets people throw away and you can find on craigslist, do a search for "pallet pen/pallet coop" and you'll probably find some of those if interested.
God bless,
Daniel.
