Chicks

• During the first week of their lives, chicks need 90- to 100-degree F temperatures. Use a 75- to 100-watt bulb, and adjust the heat lamp according to the chicks' behavior. If they are huddling tightly together under the lamp, they're cold. Lower the lamp. If they're scattered throughout the brooder, the lamp can be raised.
  
  

Pullets

• After about 60 days, when the chicks' feathers are coming in, the lamp can be removed. If nighttime temperatures are above 50 degrees F, the pullets can be safely placed in an outside coop.
  
  

Adults

• Adult chickens are usually very tolerant to the cold and usually do not require a heat source in winter. However, hens may stop laying eggs because of the cold temperatures and short days of winter. A heat lamp in the hen house lengthens the hours of daylight and may entice hens to lay eggs in the winter. Most breeds are not heat tolerant and the heat lamp should be removed during warmer seasons.