They'll be ok. I had my barn open until midnight while I was working on
the siding. Yes I was working on my siding at nighttime in 20 degree weather.
During that time all the water iced up and even the eggs I didn't collect had become
rocks. The 2 week olds in the brooder were ok. They were huddled but ok. Even
with the 125W heat lamp it was probably 35 in the brooder.