Thanks, Don and Gordon! I do let my chickens free range as much as I can, but there are times when hawks come around, so this system saves them. Plus, when I start the breeding and hatching, this method keeps them in the breeding groups I want while still keeping them on good pasture and happy. Last year, I let them eat down and till up each area completely and when I moved the pen, I planted a chicken forage blend. I will do that again this year with all of them. As long as I am diligent with moving them before it is all tilled up, the "pasture" grows back nicely.
One thing we are going to be looking at this year is the summer heat. Of course, it doesn't get real hot here, but this coop is better suited for the cold. I would like to add a couple windows covered with hardware cloth, but have a flip down door over it for cooler days. The ventilation we have now seems to do well for the moisture control, but not as much for cooling off in the warmer days. So that is something we are looking at improving on.
I do like the sand much better than the pine chips. I use sand in my brooders, too. Stays much drier, easier to clean, and the chicks get their first taste of natural grit. I have learned, though, that the chickens dust bathe inside the coop a lot with the sand! That is fine, but the Ameraucondo girls are doing it right by the nesting boxes, which makes for a very messy nesting box! What is good about that, though, is I put DE in the coop sand now, since they are dust bathing in it, they are making it easy for me to keep them mite and lice free. The cleaning of the coops is easier with the sand, too. Just need a kitty litter scoop. I get play sand from Lowes or the hardware store. Some people prefer the construction style sand, but I like the finer grain...makes it easier to scoop the poop out. The sand also is a great insulator for keeping them warm.
The way I designed the roosts in that U shape and a flat board....the flat board makes it to where they sit on their feet, keeping them warm. We were going to see how they did this year in the sub zero temps, but we haven't had that frigid cold yet! But if they still struggled in that intense cold, we were going to put some heat tape on the roosts, like the kind you put around pipes...doesn't get too hot for their feet, and gives just a touch of warmth on their bums to take the chill off, without the risk of fire. We haven't done it yet, because we don't know if they will need it, and we haven't had it cold enough here to test the warmth in the coop yet. The U-shape keeps their body heat centralized, too.
As for capacity....the coop measures 4X8, but about 1 foot in the front is the platform and ramp down, so the interior is about 4X7. Right now, the most I have in one coop is 11, and they all roost on one side and about half of the back. So theoretically, I could easily put at least 5+ more birds in there without crowding them. Now, in the summer, I am not sure I want much more than that in there unless I get the windows in to let air circulate more to keep them cooled off. That's a lot of body heat! But the 11 roost lined up, and still have room to stretch sporadically. I actually sat and watched them one night just to see how they fared in the space capacity. These are full grown New Hampshires, Delawares, and Barred Rocks, so large sized chickens. Not as big as Jersey Giants or Brahmas, but bigger than Ameraucanas. The pen is 10X10 with two roosting bars running the length of the sides. Plus the ground under the coop gives approximately 130 square foot of ground. Only 100 square foot gets rotated unless I move the coop, too. It takes my 11 about 3-4 days or so to clear out the grass in that area. And especially when I have the tunnel in use, they run around back and forth a lot playing and having fun. It is so cute watching them go through that tunnel! It is like a game to them. And they all line up on the bars a couple times a day and rest. In the spring and summer, I dont' have the top tarped, just poultry netted. They bask in the sunshine, and the run under the coop gives them breezy shade. and protection when it rains.