There is not a single temperature, but rather a range of temps, mine have good wind protection, and are comfortable from, -10 to +90. They will survive -20 but will need more feed, and +100, but will need more water and shade. mk
I know that chickens can tolerate a wide range of temps and that some breeds are more tolerant of heat, others of cold. That being said, I would guess a range in the temperate zone of, say, 50-70 degrees F. How did I arrive at that range? I think the most abundance of life on the planet are in that range so it is the zone that is most tolerable, especially to land based life. This is an educated guess at best, so do not quote me, please! Just trying to stimulate the conversation!
I've not seen mine look cold, yet. I got Buff Orps since they tollerate a wide range of temps. It was really hot here this summer and I provided at least a frozen water bottle when it was over 100 deg. They are about 22 wks old now and the temps are comming down (finally) so its in the middle to upper 80's during the day and upper 60's at night. Their coop is a playhouse converted to chicken coop and is very 'airy'. I just wonder when I should make it more warm for them in the evenings, the only time they are confined. So I guess I should plan on trying to keep them in about 65/70 degree temps.
Does anybody know at what temp. a big, fluffy chicken gets cold?