Ditto for chickens being hardy...this is my first winter owning them and I asked my sister (who lives in a state much colder than ours) how she heated the coop. She said she didn’t because then the chickens acclimated to the cold and would still want to get outside every day; her neighbor has a heated coop and his chickens won’t budge. She has hilarious video of her chickens and ducks plowing through deep snow! We’ve had temps dipping toward single digits lately and mine are still trying to bust out the coop door, haha.
With all that said, the silkies look a bit more delicate to me, especially since they’re young.