Here is an alternative to using metal, which has risen in price the last couple of years: I found plans online for a PVC frame pen. I built it in a day with a little help from my hubby and 13-year old son. It measured 10'X10'X2-1/2' It was very easy to build and lasted 2 years before I took it apart. The reason I took it apart was that is was coming apart due to the fact that I did not glue the joints so that I could dissassemble it. But, if you have somewhere to put it when not in use or during the winter, then you could just leave it. I used it as a moveable structure, and it worked wonderfully! I first had my hens in it and built a nest box for them to lay in and I made a roost that could be moved along with the rest.
I had to special order the joints for this since the t-joints are not readily available at places like Home Depot. It cost about $100 to build one.
I also used this to put my meat birds in for the last 4 weeks. With 8 hens I had to move it about once every 2-weeks. With meaties that crap constantly, it was every couple of days.
Since the PVC is lightweight and round, it will slide across the ground.
We live on the prairie and it gets mighty windy here and I staked the corners and the tarp down so they wouldn't blow away. I used the corkscrew stakes from
WalMart that are used for tying out a dog on a cable. Those a few bungee cords and I was set.
I also built two wood framed tractors with metal roofing over half. It is heavy as heck and without the wheels (which the first ones came off from weak welding), we had a heck of a time getting it moved. They are great with wheels. The only other drawback for them was when we got really heavy rain, it puddled up in it on the low side.
Don't know why the wrong imagaes loaded last time. Oops.