I have two heat la,ps in my hen house. They wil get plent y cold when they go outside. The la,psmare just s easy for me to get a little comfortable. It is true though, buff orphingtons area much larger breed and can tolerate cold. I'm guilty of spoiling my bantams and my big chicks. I have a fan for them in the Summer. One of my barred bantams had a heat stroke so we had to do something and they love it. Good luck.
You're in Louisiana, right? What are the lowest temperatures you get?