I wasn't planning to use a heat lamp (still not, except maybe just this once) - not a fan of the fire hazard or the idea that if they aren't used to the cold it can hurt them if suddenly the power goes out in the dead of winter.
However, we just had a major drop in temperature from yesterday. It's been hovering around 24-26 during the days and about 14 at night. Today, it's gone down to -13 and it will be colder tonight. I decided to keep them in today until they've acclimatized,but of the hens are shivering in the coop, which is well insulated (more than it should be - it actually needs more ventilation but that's for another discussion). I've been topping their water up with hot water and making sure they aren't getting frostbite, but watching my one hen shivering to no end trying to lay her third egg ever just doesn't sit right with me.
Would it make sense to put a bulb in there, probably just til tonight, to let them get a little warmth? It would be well supervised - I can see the coop from my office window, and we check on them often. I'm concerned that if they couldn't handle a power outage, a drop this dramatic might be too much. It could just be first time hen mom worries but hoping someone can shed some light on this. It's really ****** cold out there. I have a light that can hang from a hook on their ceiling, it's not super big though as we only have 4 chickens. Looking mostly for advice from people that generally don't heat or only sometimes heat their coops. I don't want to make it harder for them.