Why would my chickens start molting in severely cold weather?

[Spartan22]

I got 10 hens that are 21 months old, 7 of them just finish molting last month and 2 just started molting last week, go figure!

 

[buddy18]

Our particular area in eastern Washington typically experiences mild winters -- not too cold, little to no snow. THIS winter the temperature dropped to below zero and we got stuck in an inversion that is keeping things frigid. Oh, and nearly two feet of snow!

Needless to say, my chickens think the world has ended. Some days it is simply TOO cold to leave their door open -- and they're not interested in coming out anyway. They have lots of room in the unheated coop, ample food and heated water, fairly deep bedding. Everyone is getting along well as always (no aggressive birds). I'm even getting a few eggs.

A few days ago I noticed a couple of feathers. Today there are TONS of feathers, and I noticed that most of my 2-yr-old easter eggers are MOLTING!!! They have naked spots all over, and a couple have no "bloomers" left around their vents!

Did the weather send them into shock? Are they crazy?

They didn't molt at this time last year. And they already went through a light molt at the end of the summer. I keep the coop clean and everything is dusted often with diatomaceous earth --- I haven't seen any signs of mites, but maybe I'm missing something. The other birds - Polish and Cochin - are not molting at all, and seem fine.

What am I missing?

You must live close to us, Kennewick Wa. Last winter was horrible! My chickens are free range as in they roost in the trees. They just showed up one day and decided not to leave so can't coop even if I wanted to. But they had frostbite, didn't even want to get out of the trees the snow was so deep. I leave the barn door open and a couple of smart ones figured at least in there they were out of the wind and falling snow. I have a couple molting right now, and just as you say, why now?