WhyDoILikeChickens
Crowing
Are you protecting them from the cold? If not, they're probably dying from the extreme stress on their bodies.
These birds are surprisingly tough. I have a heat lamp but only use it in the teens or single digits. Last winter I had 1 orpington with only a heat lamp she survived -54° alone in her coop.
But I'm creeped out about this story.