Two observations that have me befuddled about humidity, but first, I so hope your RIR babies are okay! Sorry to hear about the frostbite! @Beekissed
says to slather the combs with castor oil and I did that very thing yesterday to my hens!
can weigh in here about my points/confusion below?
1. Today the outside temp was about 7F this morning. It snowed lightly. On Accuweather it stated outside humidity was 77%! What is up with that? I am so confused. IF it is THAT high with these low temps, I doubt I could vent a coop to reduce ANYTHING and should just leave chickens in open air and they would STILL be at risk.
2. Yesterday I opened the Big Cleanout door (almost an entire wall) for several hours to see if that would reduce humidity during the day while the chickens were in the run...thinking that level of venting would bring inside humidity down. NOPE. Nothing changed.
I am flummoxed.
2 and 1/2. This morning temp 7F. Inside coop 17F. Inside coop humidity 72%.
SMH. I don't get this AT ALL.
On a relatively calm, clear night with an arctic airmass in place, the ground loses heat to space via radiation loss and the surface attempts to cool down toward the dewpoint. Often the amount of moisture in the air is similar outside and inside of the coop if you have good ventilation. So, if your inside coop temp tends to match the outside air temp at night, your relative humidity will run similar to the outside values. If your coop runs 10F warmer inside than out, you will tend to have a lower relative humidity in the coop assuming good ventilation. Cold wind is bad when directly hitting the birds, but it does tend to mean lower relative humidities. Keep the drafts off of the birds and they should have no problem with those types of airmasses so long as you have cold hardy breeds.
I like to put a ceramic heat emitter directed on my leghorns on the radiational cooling nights where it can be -20F with 90% RH by morning. Again, if you're near saturation outside and your coop temp is similar to the outside air, you're going to have trouble bringing your RH down much unless you add a little heat or a dehumidifier. I'm struggling with my leghorn dilemma right now too. It's currently -2F with a dewpoint of -15F and a relative himidity of 54%, but my leggies got a tough of frost bite with the outside air at 3F and 90% humidity.