I've seen a lot of pens like yours Bigb and they all seem to be low to the ground. Is there a reason for this? My cages were originally grow out pens for chukars and pheasants. They are 3 foot wide and 6 foot deep. The floors are small wire and my birds have never stayed cleaner. They all have baby saver wire so I can put even chicks in them. For me, the best thing is the size. I can easily fit a small flock in them with lots of space or use then to as grow out pens. The wire allows them all some sunning time but they are able to stay back on the opposite end in the shade so they choose what is comfortable. They definitely get a lot of fresh air and sunshine though. Mine are a good 4 foot off the ground so I don't have to bend over to put fresh feed/water etc and room for nest boxes and tall enough for the roosts to be well above allowing more floor space. The downside to this is that I can't reach in so easily to catch them but the good thing is that they have all been taught to come running to me for treats and the roost is close to the front so I can easily pick them up when it's bedtime. I use a broom occasionally to brush off any poop that sticks to the wire when it's dry but that's rare.
I think if I got more pens, they would be like yours but wire floors and higher off the ground. I love the dimensions you have for breeding pairs too so I think if anything, for me, I would want them just like yours but with plastic coated wire floors and taller legs. Another thing you could add is a door between the cages, hinged at the top with a snap lock to hold it open should you need a larger area for a rooster with 2 or 3 hens. All that said, I love the design and look of your cages, nice clean lines, simple and effective. Mine are totally wire with a metal roof and I have shade cloth on the back, it's the west side to keep from frying them. I don't need to worry with cold because I bring them in when it's freezing anyway.
It got to 13 below last winter here. We have had some really nice winters here that they could be outside with a light over the roost but we're also prone to terrible cold without a lot of warning so I figure I will always need to have them inside in the winter and out in the summer, period and trying to hope for a mild winter is futile. I've found that planning ahead that way has been better in the long run than suddenly having to find enough cages and space in the garage to bring them inside.
If I get lucky and get the portable building my husband is trying to buy, I want some outside runs but haven't decided yet if they will be on the ground or wire runs attached to the outside walls. I kind of figure they will be off the ground though. I figure they will be for chicks since I will bring the adults out to the larger pen in the summer. That way, the chicks will have the inside/outside option when they get a little older.
After I have all that set up, my next goal is to find a smallish, old greenhouse frame to cover with welded half inch by 1 inch wire, a section of shade cloth and use as a chicken tractor to give each breeding group a few hours out on the grass when I'm home. I may even set it up on a short wall of concrete blocks and fill in with good dirt, plant with beneficial grasses/plants for them to nibble and an edible vine on one end for wind break, a large flat pan of sand and DE and things to fly up on for fun......and a ornamental concrete park bench to set on to watch them safely play and give them treats......I say Dream Big
edited to add: Mine all had fans on them this summer. It wasn't a luxury, it was necessity