Hi there jprs!
We didn't fence in the bottom, I weighed the pros and cons, and decided against it.
We used 3/4 inch 10 foot long PVC. It was sch 40 thickness but I am making a second coop for a friend and and found there is a thinner pvc that renders greater flexablity. I'm not sure it will hold a screw though, however, it is much easier to work with than the sch 40. So far it seems to be ok:
I'll update here on how it goes with the changed PVC. I hope the second one doesn't take as long since I made all my mistakes on the first!
Started building mine today. Went with the grey electrical conduit as it is UV rated. I do have a new question. What is the 1X4 about a foot off the base for? It seems like you would want it higher up for stability, but is it needed at all? I'm trying to cut weight where I can, because of modifications to the coop.