Thank you for that link! We are about a month out from our typical first snow and this was on my list of things to research. As for your dirt suggestion, we have acres and acres of that so I can easily line it with dirt. My girls have never experienced dirt outside their dirt bath. So I am not certain what their behaviors will be just yet, but I in no way wish to cause them harm by not lining the run properly.
Of course! I thought that would be very useful given the numerous articles linked.
Perfect, you can always switch the dirt every once in a while then. We refresh ours every other year (they free range so it is less important for us). You can always play around with it with adding different mulch amounts. Just as long as they have a spot to take a dust bath.