Picture of our chickens today, outside at about ten degrees above zero.
"Do we need a heat lamp for our chicken coop?" I get asked this question often, and there isn't an easy "yes" or "no" answer, as there are a lot of variables to take into consideration, most importantly; your climate, how well insulated your coop is, how big it is, and how many chickens you have.
First, the Fairbanks area ranges from zone 1 to 3, due to micro climates and a weather inversion that traps colder air in the low land. On our hill I believe we are in zone 3 territory. This winter we are experiencing warmer temperatures than normal, mostly 0-20 above zero Fahrenheit. But some winters we see a good deal of 0-20 below zero as well. We usually only get a few days colder than that here on the hills. We do not use a heat lamp for our chickens, although at times in the past we have used one on a timer when we had a more spacious and less insulated coop. For the last two years (out of 8 total winters with layers), we have noticed that our chickens are happier in our smaller coop that is dug into the side of a hill, framed out and well insulated with one narrow door in the front. The ceiling is probably around 7 feet from dirt to ceiling in the summer, but we let the deep pack bedding build up and currently there is probably only five and a half feet from floor to ceiling. The dimensions of our coop are 7x9 feet, giving us 63 square feet of floor space. We have twenty layers and a rooster, which is the limit for this small coop. It works out to only three square feet per bird which is less than the recommended four square feet per bird. Having lots of places to roost and a covered and sheltered outside area with straw on the ground, helps make the most of our small indoor space. We run a forty watt bulb around the clock because I haven't gotten around to putting it on a timer, and the chickens seem to do fine. We also use an electric heater for the metal galvanized water container. The low watt bulb and electric water heater combined are just a fraction of what we use to pay when we had a heat lamp on a timer.
The biggest question I would ask you is "How cold does your coop get without a heat lamp?" If your answer is below 20 degrees F, on a regular basis, you will want to consider some different options, which need not be exclusive to buying and running a heat lamp on a regular basis. Our coop stays above freezing without a heat lamp and our chickens are fairly happy considering that they've put up with several months of a dark cold winter and limited indoor space already. I do believe that your layers will do the best for you if their coop temperatures are higher than the number I've given. I think low forties is an ideal coop temperature for our climate. That way they don't get so climatized to warm temperatures that they don't want to go outside when it is 20F. Nor is their coop so warm that it is humid and real stinky, which can cause respiratory problems. So, wherever you are, think about the difference in your coop and outdoor temperature. Obviously you don't want it so extreme that your chickens don't want to get outside for fresh air. Our chickens go outside daily for at least a few hours, unless it is below zero, in which case I leave them closed in with extra kitchen scraps.
As far as coop temperature goes, chickens can tolerate lower temperatures than this. However, our priority as livestock owners is to see that our animals have their basic needs met; clean water, proper food resulting in good weight and health, and the correct living quarters - which encompasses coop size/chicken numbers, artificial or natural light, indoor air temperature, access to the outdoors and fresh bedding. If all of these conditions are met, than your chickens, whether they live in a zone 1 or zone 5 climate, should be happy. I consider my chickens happy this time of year if they are all upright and alert, eating well, rushing outside to get their daily scraps, they all have good plumage without any (or much) pecking and are laying well. If you have older birds, it may be hard to tell if they are laying well, as their production starts to drop off. If I have a mix of young and old birds I'd like to see half as many eggs as there are chickens a day. Right now a quarter of our flock are two year olds. We are getting 12-16 eggs a day from twenty hens. Your hens may be able to survive some pretty cold temperatures, but they will lay better and be healthier looking birds, less prone to sickness if you can keep their coop above freezing.
One of my more raggedy looking, timid Welsummers above and our rooster behind, who ironically has been getting his tail feathers pecked out by the more dominant females.
If you have a well insulated chicken coop that is the right size for your birds you shouldn't need a heat lamp. You may need an electric heater for your galvanized metal waterer and this way your birds always have access to water. An electric heater, while more expensive initially, will be far less expensive to run than a heat lamp. All coops in areas where there is less than twelve hours of daylight need a source of artificial light in order for the hens to continue laying well in the winter. Fourteen hours of light is recommended, and this light can and usually does provide some heat, but does not have to be near as expensive as running a heat lamp. A 40 watt bulb for 14 hours a day makes way more sense than feeding chickens all winter and hardly getting any eggs. Running a low watt bulb will produce some heat as will your electric water heater. Another source of heat, not to be underestimated, is the body heat that the birds produce themselves. In addition, if you are able to let bedding build up and begin to compost, while weekly adding more fresh bedding to the top, the ground will stay thawed and will produce it's own heat. Now, I realize that if you have a traditional wood floored barn, this might not be the way to go. But this is a reason that I am a fan of dirt floors for goat housing and chicken coops. After spending many nights sitting on the floor of our goat barn waiting for goats to kid and soaking up the warmth coming from the composting bedding, I am sold on deep pack bedding practices.
I have a friend whose chicken coop is dug into the ground, and a fine example of a subterranean earth dwelling. Her chickens, goats and rabbits live in here together year round. If she has any problems, I would guess that it might have to do more with humidity issues than the temperatures ever running too cold for the animals. The chicken coop that we use in the winter is about 7x9 feet and is dug into a hillside. It is framed out with insulation and a narrow door on the front. My husband says that the insulation for the coop is R 38. A well insulated coop is really the way to go. If your coop lacks in thickly insulated walls, you could try surrounding the inside walls with straw bales, or if you don't have room inside, you could build them up around the outside. Make sure you have enough chickens to heat your coop. A general rule of thumb is four square feet per chicken. I think that in cold climates, you want at least this many birds to heat your space. And hopefully you don't have really high ceilings in your coop, because a lot of heat is wasted this way. I'd consider building a drop ceiling in the coop and storing straw bales above, if I had a tall chicken coop. Electricity is expensive! So, if all else fails and your coop is still too cold, then and only then would I consider using a heat lamp and I would put it on at timer to come on during the coldest hours of the night. You can get a red bulb if you don't want to disturb their sleep/laying cycle. Buy a cheap timer and a thermostat so you can keep track of the temperature lows and highs. Have your lower watt light bulb still come on for fourteen hours of daylight.
So there are a lot of other options to warming up your coop than a heat lamp. If you do use a heat lamp, put it on a timer and save yourself some money. We use a heat lamp for brooding chicks in the spring and that is about it. If you design your coop well and it is well insulated with appropriate numbers, you should not need to run a heat lamp throughout the winter even in the coldest climates.
Best wishes to you and your chickens. Please let me know if I've forgotten to touch on any key important details or if you have any questions regarding this post or my chickens. And as always, I enjoy hearing other's experiences and opinions and I will readily share them.