The bottom line is that the chickens need to be protected. A dirt floor will work, but as the rains soak into their house, and you walk into it, do you want to be stepping in the mess?
If you are in a climate that drops below zero in the winter, then the small cost of insulating will allow you to sleep a little easier at night. Generally, chickens tolerate cold well, without adding heat or insulation.
Windows: just make sure that the summer evenings won't be too hot. Put in more than one window that is openable, and use wire mesh on the inside to keep the predators out at night. In the winter, the windows will be closed. Make sure your coop is weather tight and has no drafts. A little air leaking in is fine and will keep the humidity down (which discourages fungus). So...a little air exchange is good, but no drafts!
Other than that, build the coop out of any material you like, just keep it rain tight, draft tight, and predator proof.
Hope this helps you.
Brian
If you are in a climate that drops below zero in the winter, then the small cost of insulating will allow you to sleep a little easier at night. Generally, chickens tolerate cold well, without adding heat or insulation.
Windows: just make sure that the summer evenings won't be too hot. Put in more than one window that is openable, and use wire mesh on the inside to keep the predators out at night. In the winter, the windows will be closed. Make sure your coop is weather tight and has no drafts. A little air leaking in is fine and will keep the humidity down (which discourages fungus). So...a little air exchange is good, but no drafts!
Other than that, build the coop out of any material you like, just keep it rain tight, draft tight, and predator proof.
Hope this helps you.
Brian