When I hatched 4 little Seramas, I was prepared to give them heating lamp when the temperature below 32F. But last night I forgot to turn on the heat lamp, and it was 16 degree this morning at 7:30am. I opened the mini coop I built for them, they are alive and well. Last week, the night temperature dropped to 3 F degree, even I turned on the 75W heat lamp, I still worry they might freeze to dead. But it was only 5 degree inside the run early in the morning, I opened the chicken run enclosed with greenhouse films, they still willing to come out of the coop to eat and drink, and spent whole day in the run. I let them free range in the back yard a couple of hours even when the temperature was 22F. The little Serama roosters still like to stay outdoor even the temperature was around 20~25 and windy! I was surprised, and I guess they are not as delicate as we thought. My Serama roosters are about 14oz, very tiny compare to other bantam hens. The key is let them acclimate to the weather slowly and naturally. Once they get used to the cold weather, they are tougher than we give them credit for.