My first winter with a pair of chickens: 5 x 5 petsafe dog cage with predator proof top (Coop)
hardware clothe around bottom with big rocks and timber bordering bottom to discourage predators
fully covered coop with tarp
stacked bales of STRAW shoulder high around coop and some straw ontop covered with an old tempered glass window to keep straw from flying away
thermal sheeting zip-tied to door to keep drafts out
stacked bales of straw INSIDE coop, and put a one-shelf book case for a nesting box (measured about 2ft x 1ft x 1ft)
in the winter I gave a cereal bowl full of water in the morning and night.
What happened? We free range, and check this out: on one of the blusteriest and rainiest days of the year, the coop door closed - we came home to 2 chickens DRENCHED waiting right outside the coop door to get out of rain no doubt. Terror struck, because I read chickens need to be kept away from drafts and wetness. Agh! They don't have a chance (or so I thought).
Turns out they were just fine. Furthermore, on the coldest day of the year, -30 with wind chill, our Amelia had her first egg ))