thomas rubino wrote: If Chickens are like pigs, they will huddle together to stay warm.
From an incredibly young age, you can trust chickens to be heat seekers. I had to move a young chick into a Muscovy duckling shelter and I was relying on the Muscovy mom + 5 half-grown youngsters to keep the chick warm overnight and he did just fine.
We have moved to rubber buckets for freezing weather. They tolerate having hot water poured into them, and they're easy to flex to get any ice that forming out of them. Size matters - it is easier to keep some water unfrozen in a larger container than a smaller one.
Using old sheets to trap heat in a smaller area than the whole coop will also help. We're more likely to find birds sleeping in nest boxes instead of on their perches when the weather is
fowl foul (yes bad pun... couldn't resist), so if you're really worried about the young birds, a large cardboard box with bedding and a chicken-sized entrance will help them "cuddle up". Just cut a few extra holes for air! With my last group of pullets with an adult "mom," I used a dog crate to accomplish this.
Hopefully it will all go well.