We usually keep our chicks inside the house until it is warm enough outside. But last time we had chicks, my SIL and her family were coming to stay, and she has bad allergies to ALL fur and feathers. So...
They were probably about 3 weeks old at this point, starting to feather out, but still tiny and mostly down. We had 9 chicks. We had warmer days and still cold nights; our chicken house gets quite warm when the door is closed during the day.
I booted the adult chickens to the covered run and that left the 4'x8' house just for the chicks. For the first week, we did the following Morning, noon and night. After that, it was just before bed.
We took some homemade rice bag buddies, you know the ones you warm in the microwave? We heated those, put them in a ziplock bag to protect from poop, and then covered those with a pillow case.
Then we put those inside a small cooler, tipped on its side, near the wall farthest from the door. The chicks slept on that all huddled in a pile.
We kept their food and water close to the door, so they had to move around a bit to eat.
It must have worked - all 9 lived. I think we kept that up for a month before it got consistently warm enough and they feathered out more.
