We moved the girls into their bigger, better brooder (4' diameter kiddie pool surrounded by hardware cloth, and some scrap lightweight foam sheeting that was packing material in a big box laid over the top to prevent escapes...they're trying to fly!).
It took them a while to understand the heater plate (even after I put them under it), but now they're all snuggled under it, quiet and seemingly happy... except for one little guy. I'll check back on them in a half-hour or so and see if that same lone hen is out from under. Which could mean, I guess, that he's just hardier...though I worry he was kicked out.
View attachment 2114219