When he first visited, my friend Harvey Ussery was fascinated by the way I house my Leghorn chickens. Since then he has encouraged me to write an article sharing my thoughts and experiences on using Open Air pens.

My chickens do not have a tightly closed building to protect them in winter, but rather pens with half a roof and a tarp on two sides to block the wind. Most people would expect my Leghorns, with their large combs, to suffer frost-bite and to do poorly. But, in fact, they thrive in my pen system. How?

Fresh air and exercise help chickens stay healthy and withstand winter better than most people realize. Photos by Don Schrider

First we have to understand that our animals are healthiest when we give them conditions that allow them to express their natural instincts and which imitate their natural environment as much as possible. Chickens need to scratch — moving around all day in search of food, kicking with their legs and exploring with their beaks. They like to get up off the ground and perch, especially at night. On hot days they seek a shady spot; on cold days they seek a spot warmed by the sun. They need to dust bathe to keep insects off their bodies and to remove dry skin. They like to have some cover.

Next we have to understand what good health is for chickens and how it affects them. I actually came to understand this first with my flock of sheep. We had a friend that had no buildings for her sheep — only groves of trees and windbreaks. She had almost no health problems with her flock while some of our ewes always had runny noses in winter (pneumonia). We ran our sheep out of the barn and never had runny noses again! What made the difference? Clean air and exercise.

When animals defecate in a building, ammonia is released. When there is enough carbon matter in the litter, the ammonia is trapped. When there is not enough carbon matter, some of the ammonia evaporates and you can smell it in the air. Lung tissue is damaged at five parts-per-million of ammonia — our human sense of smell picks ammonia up at about 25 parts-per-million. In other words, when your chicken pen smells the fumes are already damaging the lung tissue of your chickens! To compound this issue, a tight building also tends to trap dust. Dusty air further challenges the lungs of the chickens, and the building limits the amount of exploring and moving the chickens will do.

Cultivating good lung health in our chickens is a cornerstone of having a healthy flock. Paying attention to the lungs is perhaps more critical for poultry than for mammals. Keep in mind that chickens have small, relatively weak lungs. They also have nine air-sacks — hollow sections of bone that circulate air. Their bodies do not sweat, but rather heat is regulated by expelling moisture when they exhale. When the lungs of a chicken are challenged, the bird is much more prone to disease agents; it is no coincidence that most poultry diseases are respiratory in nature.

When I designed these pens, what I was looking to do was to create a simple shelter that would protect the chickens from harsh weather, yet give them lots of fresh air and a reason to exercise. Old research into open fronted chicken houses (pre-1900, conducted in Iowa, Minnesota, and Massachusetts) influenced my thinking greatly — if birds could thrive in those winters, why couldn't Leghorns thrive in Virginia winters? I also was looking for a system that would allow the chicken litter to break down as if the floor was a compost heap of sorts. Thus the half roof/half open format.

When you view my pens, you should think of how they operate. First, the basic pen is 10 x 10 foot. Across this I have a 5 x 10 foot roof. The purpose of a roof is to protect the birds from rain, snow, and sleet, give the chickens a sense of security, as well as to keep out predators. Since I wanted to keep the dust levels down, I only covered half the roof to allow snow and rain to mix with the bedding. Next, I wanted to have plenty of airflow, but wanted to break the prevailing winds and winter storms. So I placed a tarp to cover two of the sides of the pen. Using a tarp allows me to roll up the bottom or roll it back so as to cover less in the summer when more airflow is helpful. The tarp also provides some protection from sun. Roosts, feeders, and nesting boxes are placed to take best advantage of the combination of tarp and half-roof.

This simple pen was made from six sheep panels and a tarp, yet chickens winter very well under its protection.

The pens are also best oriented so that they face east. I have always preferred south facing pens, but with only half a roof there is too little shade in the summertime. The placement allows me to block the winter prevailing winds (north, and west) and the evening sun (west), which in summer can be a killer. To provide more shade in summer, I also attach some shade cloth, draped a tarp from the pen in "tent-like" fashion, and even use a plywood board propped against the pen to give a hidden recess and shade. (Chickens love little hidden areas, it makes them feel safe and it helps keep pecking and fights down when the chickens can get out of another bird's line of sight.)

For bedding I use straw. At first I tried using a deep litter of straw, but found this compacts too quickly and it was too slippery under the chickens' feet. Leaves worked well, but I had no place to store them once fall was over. I tried hay once, but I found hay molds too quickly for this pen style. Finally I settled on a light layer of straw mainly by happenstance. That is, I ran out of straw and could not make it out to buy more for a week. Observing the litter, I decided to wait and see what happened. Much to my joy, the remaining litter began to turn into dark, rich compost quickly. I then tried adding only a light layer of straw and found that my young birds no longer formed a hard pan of manure, and my adult birds would stir the litter beautifully every time I tossed a handful of corn into the pen. My nose also told me that there was no ammonia fumes to damage lungs.

Some of you might now be wondering if these pens can protect the birds from winter - and a few might be thinking it would be kinder to provide my birds with heat. Well, the truth of the matter is that providing a heat source actually weakens the birds' bodies, and the necessity of keeping the building closed causes a buildup of moist air, dust, and ammonia — which work together to weaken lungs. A better approach is to provide fresh air in conjunction with exercise. Please keep in mind that frostbite on the combs of chickens has more to do with moist air and poor circulation of blood than cold weather.

Ideal pens are not tight and heated, but rather are designed to protect from harsh winds, excessive sun, rain, and provide some sight barriers and cover for the home flock. These pens function beautifully in summer or winter. Notice even a propped sheet of plywood can be used to block snow or sun.

Did you ever play in the snow? (I'd say "as a kid" but some of us still enjoy sledding, etc.) Ever notice how once you get moving you get warm? This is because your heart rate increases as you exert yourself. Thus the old adage, "Firewood warms you twice: once when your split it, and once when you burn it!" The circulatory system of the chicken is of great importance. Give them fresh air, loaded with oxygen, and a place to scratch and their bodies will become warm.

In cold weather you will notice your chickens' habits change a little. They will seek cover less often, preferring to take advantage of sunny spots to warm themselves — their habit being to follow the sun as the day progresses. You will see few avoiding each other - almost as if their "personal space" is now smaller. They will also hold their body feathers up a little more, trapping more warm air. When provided a small pen, chickens in winter will be very sedate. But when you add a daily scratching opportunity and a larger pen, the chickens become more active. I would never go so far as to say that chickens are more active in winter, but healthy chickens will be more active in winter when given more space to explore.

It has been a wisdom to feed chickens scratch feed toward the end of a winter day. This practice is eminently valuable for three reasons: First, scratch feed is usually composed of corn, which gives fat to burn to stay warm, and often of wheat, which causes more heat when it is digested. Second, tossing the scratch down in the bedding not only employs the birds in turning and freshening the bedding, but the exercise warms them and fulfills their natural instinct and desire to scratch. Lastly, a chicken that has just eaten mash will always find more room for scratch feed — thus your birds will go to roost with more food in them to help them stay warm all the long winter night. This is especially important. Consider that in winter, when more calories are needed to stay warm, the birds have fewer hours to find food and a longer dormant period (night). But one should still monitor the body condition of the birds so as not to get them too fat. [See my article "How to Get More Eggs" in April/May 2010 issue of Backyard Poultry.]

My pens work for me and my chickens because they provide the chickens with what they need: fresh air without moisture and dust; wind breaks; shade; protection from rain; protection from driving winter winds; protection from predators; exercise; sight barriers and places to get away from each other; places to sun and to dust bathe.

Try spending time in your chicken pens and see if you are comfortable — if you find them smelly, dusty, or cold, then maybe you need to make a few changes. Enjoy your chickens and the compost they produce!

Two great articles on ammonia can be found here (PDF) and here (PDF).

Don Schrider is a nationally recognized poultry breeder and expert. He has written for publications such as Backyard Poultry, Countryside and Small Stock Journal, Mother Earth News, Poultry Press, and the newsletter and poultry resources of the American Livestock Breeds Conservancy.

He is currently writing a revised edition of Storey's Guide to Raising Turkeys (and welcomes all turkey comments and contacts). He can be reached at brownleghorn@gmail.com.

Text © Don Schrider, 2011. All rights reserved.