Courtney, I have experimented with a lot of designs from tractors, dog kennels to hutch designs and they all seem to have pros and cons. But, those are nice pens for a couple groups of birds. The 4x8 module is a good start because of the material dimensions. 4x4 is good for a trio of LF or you can do a pair in a 4'x32" so you can get three pens in the 8' length. I would add more overhang on the sides and maybe the front. Also I would always have a solid wall along the ground up to approx 24" or so. Even small dogs can go thru welded wire fabric or chicken wire if they really want it. And I've had that happen a number of times thru the years. One other option is to make it 2 levels, second level up about 4' off the ground. You have to reach a bit to catch a bird once in a while. But you get four pens under the same roof. Also IMO you might want to plan bigger. Two pens are a drop in the bucket if you are at this for any length of time. But you can make in 8' modules in case you have to move it down the road. You might want to place paving stones, wire or an elec fence around the bottom to deter night diggers too.
Its great if you can develop some individual pens too. These are great for pair matings, conditioning, or letting a bird rest or recoup. My hens need a rest during the breeding season from the males. LF are very rough on the females during the season. He can have his own little cage for several days and visit a couple times a week if you are still hatching. Or you can keep the hens in their own individual pens and rotate him from pen to pen. You know for sure which hen is producing the best youngsters in pair matings. Max posted a design for a bank of conditioning pens a year of so ago that seem to be working well.
http://ameraucanabreedersclub.org/forum/index.php/topic,2156.0.htmlRoosts can be 2x4 lumber at about 24-36" and nests can be anything from buckets/landscape pots to a 10x12x12 tall box. I have a few pens where I have a 12x32" board leaned into the corner for a nest. Just a dark space where the eggs are protected during the day. I use 1 gal cans for water and feed fastened to the wall near the door. I get these from our church kitchen before they go to the trash, and they go to recycling when they begin looking old and rusty.
I am hoping that Paul with get around to "breeding and grow out pens" with one of his installments later on. I've been looking for pictures of his setup for a while.
Our birds pretty much stay in most of their pens full time unless we can group the hens into Large summer/fall pens. I have heard lots of folks that put all the cocks in the same pen for this period, but have never had the heart to watch them fight the first couple of days.