We have had the same set up for 3 yrs. Never had an issue, but we have lost multiple birds to the cold this yr. honestly my birds have never had to endure temps this low. We lost 10 birds last night alone. The wind chill was 10 bellow. The chickens are in the same type of set up, no chickens or ducks lost. No signs of illness. Just the extreme cold temps. We had a gorgeous flock of 11 different colors of birds. Now we are down to 4 guineas!!!!! The next 2 days the temps are going to stay low, not sure if the other 4 will make it. Not much else I can do to keep them warm besides lock them in a dog box with a lamp on it. But honestly they would prob beat their heads to death trying to get out of the box!