Thanks for all of your help. When I checked them this morning, there wasn't frost on the window (we haven't added the vents in the roof yet). But I did make some changes the last time I checked them yesterday.
1) I really took extra time to address the waterer - they've been spilling it/throwing shavings in it. I can't hang it because one of my hens likes to roost up in the top where the bar I hang things. The food is hanging but she always pooped in the water. Plus I kept spilling it everytime I took it down to clean/refil. ANYHOW, lastnight I cleaned the heated waterer and put it up on scraps of 4x4s we had laying around. Now they aren't spilling it or putting as much of the shavings in the water. I also scraped any ice out (from spilled water) and put fresh pine there.
2) I had been (for 2/3 nights) making them "tea" - just boiling herbs and putting it in for them warm as a "treat." Maybe the warm vapors from the tea created a problem? I was doing it basically because I could/wanted to.
3) this isn't a change but an update: one of our Wyandotte hens had a small site that was bleeding this am. I wiped bag balm on it (frostbite?) but that's all I've been able to do. They otherwise seem fine except the rooster (aracuana) keeps laying in the shavings.