Will the flock be okay in 0 degree temperature? Plus molting hen!

[Annalyse]

I don't think it's necessary to cover the fence part with plastic, since that's just their run - but it wouldn't hurt. It's the coop I'm concerned about and that big window. Cover the window with plastic, but leave a gap across the top, maybe 4 inches wide or so.

That big window is the run the coop doesn’t have any chicken wire just small tiny window that are closed.

 

[Annalyse]

Here’s more pictures from the summer time. Any chicken wire in the run is covered

 

[BarnyardChaos]

Here’s more pictures from the summer time. Any chicken wire in the run is covered

Ahhhhh what a difference good photos make! I am envious of your coop and run setup, very nice job! I love how you arranged their spaces, everything is protected from rain/snow/ice, plenty of ventilation (love the addition of louvered vents between spaces), nicely sized and placed roosts, just all of it. Your chickens will be FINE in the cold weather.

But now that I've seen everything, allow me please to revise everything I've said to this point, or confirm it below. You could leave everything as you have it now, and they'd be fine. You've done great! If you want to make them even more comfortable and ease your own anxiety, then do this (some of it you've already done, I'm just re-stating it):

The wood fence boards with gaps between, I'd cover them with plastic.

The big wire covered lower window below the coop area, I'd cover with plastic.

The big wire covered upper window next to the coop in the run area, I'd cover with plastic but leave the top 6" or so open for ventilation, just until temps warm up a bit, then uncover it again.

Scatter some straw on the dirt floor to give their feet some better insulation against the frozen ground. They'll also stay busy scratching around in it, generating internal heat.

In short, cover anything at or below roost areas with plastic and straw to stop any drafts that could reach the birds and minimize heat loss, while still allowing moisture to escape upwards and out.

That's it!