There's a reason springtime is typically the season of baby chicks. The tiny guys don't have enough feathers to maintain body temperature during frigid winter weather. Chickens breed year-round, but extreme cold can reduce their fertility. Consider it nature's way of avoiding the high mortality rates that cold weather would bring. Chicks hatched in the spring have the whole summer to become mature enough to withstand winter cold when it arrives.
Chicks' Heat Requirements
Young baby chickens have only light coats of down to clothe them. They rely on their mothers to keep warm if the temperature gets chilly. Because of this, baby chicks shouldn't be outside at all until they've grown feathers to keep themselves warm. If you're raising a brood of babies without the benefit of a mother hen, you need to keep them indoors, ensuring that the temperature of their environment stays at 95 degrees Fahrenheit until they're a week old. Reduce the temperature by 5 degrees each week.
When Chicks Can Be Outside
After two months, you will have acclimated your chicks to a 70 degree temperature -- not remotely the sweltering 95 degrees they required when they were just a few days old, nor the chill of fall or early spring. In "Keeping Chickens in Winter," an article in "Mother Earth News," Reeve O'Neill advised readers to keep chicks indoors, even if in an unheated outbuilding, at temperatures over 70 degrees until they are fully feathered, no down showing. This may take place around 8 to 10 weeks, but O'Neill recommends waiting until 12 weeks. At that point, although not fully grown, your chicks should be fully feathered and capable of tolerating winter weather.
Transitioning Your Chicks
At 12 weeks, time to move your chicks from their comfortable indoor environment to the great outdoors, transition them gradually instead of just putting them outside. Unless the outdoor temperature matches their indoor habitat's, you'll have to let them out for bits at a time at first. Construct an outdoor run that will allow them to explore the world but will keep them confined to a yard, ensuring they have access to their coop so they can escape the weather. This will protect them from predators, too. After two or three days of acclimating to the outdoor run, you can open the gate to the run and allow them to come and go as they please. At 12 weeks, your chicks will more closely resemble adult chickens than the fluffy babies they were just a couple of months before, so they should be able to tolerate temperate weather and acclimate further as colder seasons arrive.
Raising Chicks in Winter
Whether a mother hen's caring for the babies or you're going it alone, you'll need to take some precautions to ensure that your fuzzy babies will thrive in the winter. In addition to keeping them indoors at optimum temperatures early on, provide them with warm water that has corn syrup added to it, mixing 2 parts water to 1 part corn syrup. The extra glucose will give them an edge against the weather. Eliminate drafts in the brooder and the coop. Chicks who catch a chill can become sick, and they won't grow as quickly or be as healthy as chicks who don't have to endure cold temperatures. Change your chicks' bedding daily or twice a day to keep your babies clean and comfortable. And supplement their feed with corn, as it is a helpful source of additional energy that will keep the chicks warm.