Thank you for your condolences, everyone. I think I'm over the initial shock of finding her now and I've gotten myself calmed down enough to think.
Oh Pip I'm so sorry! You've mentioned her in your posts enough that I know how precious she was to you. Did she leave you with any offspring to keep her line going? It breaks my heart that you are hurting. Keeping you in my prayers.
Cricket had no offspring, but I do still have four of her sisters at least. They're all grumpy from molting, though.

I ended up giving Margie, my Silkie from Brad, lots of hugs against her will. Boy, did she have a few things to say about it! The girls seem to always know when something's wrong and a lot of them were following me around this morning. My sweet ladies.
Very sad
So sorry. I'm dreading the day I go outside and find one gone. Many times the issue is heart failure and that could have been the problem rather than the cold. If that is the case, there is nothing you could have done differently.

How old was Cricket? Will you do a necropsy to find out what the cause may have been?
I understand where you're coming from in asking, but I do know that this was from the cold. Cricket was the hen I posted a few days ago after my mom crocheted her a sweater. She had almost no feathers left except on her head and wings, and I don't think she could keep warm enough on her own after falling off the perches. She was about 2 1/2 years old.
Just to be clear,
the rest of my hens are perfectly healthy and fine with the cold. Under normal circumstances, Cricket likely would have been fine, too. However, since she had lost so many feathers, she was not able to keep warm and she had been struggling. I was trying to avoid getting her used to the indoor temperature of my house so that she wouldn't have issues outside once her feathers grew in. She had the sweater on, and I had also prepared for her a 'huddle box' full of pine shavings and molted feathers. I think that believing she would be fine under these conditions, especially after going from a 50 degree day to a 25 degree day so suddenly, was my mistake. If I had it to do over again, I would probably have brought Cricket in overnight and let her spend supervised time outside during the day.
This does not change my belief that chickens don't need a heated coop in the wintertime. I want to make sure everyone reading this understands that though I lost Cricket to the cold, it does
not mean that all chickens need supplemental heat. This is the first hen I've lost to the cold in 8 1/2 years of them living in uninsulated and unheated coops, and as I said before,
under normal circumstances it would not have happened. I know that if I had heated my coop for Cricket's sake that, though she may still be around,
I would have had 37 hens intolerant of the cold instead of just the one. It was the hard molt that Cricket was going through that did her in in the end. To reiterate,
a hen that is fully feathered does not need any supplemental heat at all in order to survive the winter. If you take nothing else away from this post, at least take that.