I'm hoping to build a new coop. It would be about 8 x 12, with a soil floor. I don't have a lot of options for location, frost goes very deep. My property is all wooded and very bony, with limited soil, and quite a few vernal pools in the areas we haven't improved. I'll probably have to put down a deep gravel base to get an area to set the coop. So, here's the question: Without putting posts down to below frost level, what are my best options to build a coop that will be stable, and will be predator proof in terms of rats and the like digging under the coop wall to gain entry. I'd also like to have the bottom 12" of the coop be rot resistant, but don't want to use pressure treated lumber in the construction. Any one in the cold weather zones have a similar sized coop with soil floor, and how did you construct it to deal with the constant movement due to frost? I think the ideal would be a cinder block base around the entire perimeter, but I can't imagine that being stable enough.