The Chance You Take When Raising Chicks in the Winter

Went to bed last night & before I fell asleep, Mom came in to tell me the electricity had just gone out. And she asked if I'd need any help with anything, such as bringing in the chicks. Usually, if the power goes out, it's only for a short time & I would have just left everyone as is. But, it was already -8*F and 4 week old chicks even with a broody hen may not survive all night without additional heat. So, out we went with out headlamps & multiple layers. I first emptied the heated water bowls & unplugged them, because without power they'd freeze solid in no time & make morning chores even more difficult.
Then, we rescued the chicks & broody hen, putting them in a plastic bin. I also grabbed Uno & Dos, the two chicks hatched by Matilda in December. 
We brought them all inside, and Mom asked, "Do you have a second bin to put them in?" I confidently replied, "Oh, they'll be ok." Yes, they were "sardines" but I figured they'd keep each other warm. However, I failed to think that through & put the bin lid back on, without much of a gap, then draped a towel over the bin. It was past midnight by the time I got back in bed.

I woke up to my alarm at 5 am the following morning, and shortly thereafter went to check on the chicks. I lifted the lid & it was warm, but very wet! The sides dripped with condensation and several of the chicks were damp. To my shock, I realized that there were chicks lying dead underneath the live ones! I felt horrible, knowing that even though I'd saved them from being frozen, I had made another fatal mistake. Not only were they too cramped, I hadn't given them enough ventilation. . They looked like they got "trampled"? Not sure why totally, but obviously there was nothing I could if about it now. So sad, as they were mostly pullets, as their rooster siblings I'd sent to auction last Wednesday. 
When I got over the initial shock, I Returned the survivors back outside when it was still -19*F. They started steaming when I put them back under the heat lamps! I checked on them before leaving in the morning and as of tonight they're doing ok. 
Life lessons can be hard at times, but it's not what you go through, it's how you go through it. 

I knew it was a risk trying to raise chicks in the winter, and I thought they be fine if I just brought them inside when the power went out. They didn't have a light on them inside, just their own body heat. But the downfall was I didn't leave a wide enough gap when I put on the lid to the plastic bin. My theory is the lid trapped all their heat inside & caused the condensation, then they got wet & chilled?? The stronger ones climbed on top & eventually the weaker ones under them succumbed.

Several things I learned through this:
1. Always listen to your mother! (As she asked if I should put some in another bin, so they'd have be more room. I thought b/c it was just temporary, I'd be fine & keep them warmer all together.)
2. Make sure there's enough space & ventilation!
3. And if the power goes out at night & you bring chicks inside, set an alarm to check on them in a few hours!

At least there's some chicks left, and I know they'll be true survivors if they make it through this cold snap we're having.

(Update: 15 chicks died, but 14 survived, 3 of which are roosters!)