ojay54 wrote: Would straw do as well as your insulation medium?
Years and years ago when I was a lad, we built a chicken house by driving posts into the ground to make walls, which were then covered with wire netting on both sides. The space between the netting was then tightly packed with hay, which remarkably was not pecked by the hens.
I remember it being nice and warm inside, as it was my job to go in there and pick up the eggs.
It also must have been cheap too, as the posts were cut from our coppice and the hay was almost certainly spoiled hay, just a few sheets of corrugated iron for the roof.
A precursor of straw build houses or a throw back to wattle & daub ?