The first approach to keeping meat hens we tried was the classic Joel Salatin - esque 'chicken tractor'. If you haven't seen these it is a small pen that is partially covered, and is moved each day. I wasn't very happy with this approach since the chickens are sleeping on the ground. Any serious rain overnight and they ended up in a mud bath by the time I could move them in the morning. Plus, although their life is a thousand times better than an industrial bird, I wouldn't consider this approach free range.
Last year we kept them in the 'turkey house'. This is a shed on skids that can be moved with the tractor and has a wire mesh floor. This worked well and the hens were happy, but it's too expensive to scale up. Also, in theory it's easy to go move it with the tractor. In reality this doesn't always happen when it should.
The first batch of hens this year we kept in the barn. Lots of room, and safe at night. But not realistic if we want to scale up, and they did not get fresh grass as much as I'd like.
This is the latest attempt, and so far is working well. It's a simple tarp covered A-frame inside of a large area fenced off with poultry netting. Rather than dragging it like a chicken tractor, this house is designed to be flipped to move it. This avoids the heart breaking accident of dragging it over top of a slow moving chicken. (The rope is so that you can flip it from the side you are flipping it toward. This way you cant make sure it is not going land in a hen.) The fenced area they are in is long and narrow, and the house is moved every few days.
A tarp is placed inside, and fresh shavings added after each move. The old litter is simply spread around the field. There is a rope around all sides so that the tarp can be tucked under it on the up hill side. This is so any surface rain water can run under the tarp rather than into the house. We haven't had enough rain yet to seriously test whether this works.
The cross pieces can be removed, and then the two sides can be folded backwards for storage. The secret to getting the tarp tight enough is to install it when the two sides are laying flat. When you then fold it into the a frame shape the tarp become singing-tight.
So far the electric netting has kept any predators out. Not having to make sure they are all safely locked in every night is a huge time saver.
I'm sure there will be things I want to change for next year, but so far this is working out great.