I just ran across this thread https://www.backyardchickens.com/threads/disease-in-chickens.1420088/
@EggSighted4Life posted an answer with extremely helpful links
You can add your location to your profile. I don’t remember exactly how but @aart posts screenshot instructions.
I’m sorry to hear this. Yes, you probably should have listened to your sister and also provided the heat lamp, BUT with the temps being what you said they’d been I can see why you...