Some people think their chickens are like humans, that they feel heat and cold like humans. Since they would be uncomfortable in cold weather they think chickens are also. They don’t understand that chickens are a lot more like the wild birds that overwinter in being able to handle the cold, even being comfortable in the cold.
Chickens, like wild birds, need to be able to get out of the worst of the wind when it is truly cold. Wild birds do this by hiding in thickets, on the ground, in hollows, places the wind is not too strong. Some people build their coops so that they are wind tunnels, don’t give the chickens any place to get out of a direct wind. As long as the chickens have a place to get out of the wind, they do fine.
Another issue is ventilation. Wild birds get plenty of good ventilation because they are not enclosed so the bad air builds up. A good coop needs enough ventilation so the ammonia from decaying poop and the moisture from their pop and their breathing can escape. By providing wind protection and decent ventilation chickens can handle cold really well.
But basically some people provide heat in the winter because they love their chickens. They really think that providing heat is good for their chickens. They have not seen chickens sleeping in trees in below 18 C (0 F) weather and doing great. They are caring people that want the best for their chickens.
