How old are these chicks? Once they feather out, I have never provided heat! I do put plastic on the henhouse to keep wind out.
I have lost many more chickens from heat than cold.
I even store water in the henhouse, sealed, to be sure that I have liquid water for the animals... my chickens are the heaters!
That sounds mean, I don't mean it that way, I remember the first bunch and how I worried over them!
My chickens are free range and have choices of where to roost, hang out, or forage.
It was below freezing for weeks last year, and a hen hatched new chicks for Christmas, quite a surprise! Those I had to use a light on and cage till spring.
I have many breeds, I like to order a mixture, get a 100 or so and figure them out. My last order was 200, I won't do that again, or will I?
And yes, I do name some of them and get attached to them.