There is no definitive temperature at which chickens need a heat lamp, as chickens are well adapted to surviving and thriving in the cold. However, if you feel it is necessary to provide a heat lamp, only provide enough heat to raise the temperature a few degrees. The hens will adjust to the cold temperature, but if it is 70 degrees Fahrenheit in the coop and 0 degrees Fahrenheit in the run, birds will not be able to regulate their body temperature. If you have chicks, they will need a heat lamp for the first few weeks of their lives, but the temperature required will depend on the age of the chicks and the temperature of the environment. For example, if home temperatures range around 75 degrees Fahrenheit, you won’t need a heat lamp past week four. But in barns or garages, which may run 60 degrees Fahrenheit, chicks need supplementary heat until they are fully feathered at six weeks of age.