I love the idea, but since i use a chicken
tractor for my coop, my guess is that a cob chicken tracker would weight approximately 40 bazillion pounds, and would need more than my wife and I to move it daily. So, until I get a crane and a forklift, I'll have to stick with my plywood and chickenwire contraption.
Go for it!
If ventilation isn't adequate, cob is easy
enough to bust through and add additional vents. All you need is a hammer and a cold chisel. My hunch is that you'll still want a big door on it so that you can easily access the inside for cleaning and such. Perhaps if you built a cob coop, you could have a door that would be easily removed. Thus, you could have a summer door which would be nothing more than a frame with chicken wire across it, and a winter door, which would be a bit more substantial -- made of plywood or something more solid. If it's just a matter of popping the pins out of the hinges and dropping the other door into the same spot, it would only take a few minutes to change out the doors when the seasons change. Or have a sold exterior door, which an old school screen door on the inside --- the way we do it on houses. That way you could swing open the exterior door on hot days to provide all the ventilation the girls need, but could close it up as needed when the weather gets cold.
Best of luck with this cool idea.
"The rule of no realm is mine. But all worthy things that are in peril as the world now stands, these are my care. And for my part, I shall not wholly fail in my task if anything that passes through this night can still grow fairer or bear fruit and flower again in days to come. For I too am a steward. Did you not know?" Gandolf
