This only took a few hours to build, a couple hours to find the parts at Lowe's (except for the special PVC fittings which were ordered online), and a bit over $200 for all the pieces.
My daughter helped me put it together.
The first occupants
The intended occupants
This worked very well for me, but there are are few things worth noting:
1. The "floor" pipe would occasionally run over the chickens' feet. They seem to figure it out quickly, though, and after a couple weeks, it wasn't much of a problem.
2. The tarp keeps blowing off. Fasten it down well, and probably figure on getting a new tarp every year.
3. It's lightweight. That makes it easy to move, but I generally staked it down every day (2 stakes worked). However, I forgot to stake it down on a couple exceptionally windy days, and it never blew away, either. No "chicken-kite" thankfully.
4. Use at least 350 to 400+ psi pipe, or it will be worthless.
5. I've heard that the PVC doesn't last very long outside. I've only used it one summer. But if the PVC pipes break, they're relatively cheap to replace. Most of the money went into buying the special fittings.
6. The instructions are all here:
http://www.pvcplans.com/pvc-pastured-poultry-pen.htm, as are the links to places to buy the special fittings.
7. When it rains "sideways" (from the east), the birds can get wetter than I'd prefer.
If I was to build one from scratch today, I'd probably make it 10x12 feet, with three 4-foot sections, rather than two 5-foot sections, with the tarp covering 2/3. That would eliminate the rain problem altogether.
I'm going to be using this for about 40-50 chickens this summer. It worked well for 30 last summer.