One of our young hens, named Jo Annie, went broody in late January (when it was definitely VERY cold) and managed to hatch out a ton of chicks, despite leaving the nest for extended periods during the setting time.
Interestingly enough, they did seem to hatch out around days 22 or 23, instead of 21, but she did an outstanding job with them. She hatched out 11 but we did lose 3 after the move to the nesting box. Unfortunately, the roosting box in our coop is a good 3 feet off the ground. The last time we had a hen hatch in this box, she brought the chicks out and when she went back to the nest, several of them didn’t make it back up the ramp and died that evening when it got too cold. It was heartbreaking.
So, now we move the hens to ground nests in a different coop, where the chicks can easily go to and from the nest. We’ve done this countless times – always at night (so the hen is less prone to vacate the new nest when we put her in) but never in the dead of Winter.
Unfortunately, it appears that 3 were somehow unable to get warm that night and did perish. Not an ideal situation and we’ll probably do some extra “post move” checking the evening we next move a hen in the Winter.
Regardless, we have 8 little bantam chicks running about with “their mama” (really a collection of eggs from the various hens that were laying at the time.)