Introducing New Chicks Into a Flock
Every other year we’re faced with a tricky chicken management dilemma. How to introduce new chicks into a flock of mature hens. Years ago, we didn’t do it right and ended up with adolescent hens persecuted by older birds. Over the years we’ve found ways to successfully merge young birds harmoniously with older hens.

Why Do It
When female chicks are four to six months old, they’ll start the most productive laying cycle of their lives. For the next year they’ll lay anywhere from 200 to 300 eggs, depending on the breed. Then they’re tired. Usually, 14 to 16 months after laying starts they’ll take a six- or eight-week vacation, molt old worn feathers and grow new ones. As they begin their second lay cycle they look like they’ve just stepped out of a chicken spa. In their second lay cycle hens lay lots of eggs but not as many as in their first year. As they continue to age egg production starts significantly dropping off.
Because we need a constant stream of eggs from our backyard coop, we plan to replace older birds with younger pullets on a rotation. Every year or two we remove about half of our old hens and replace them with young birds.
It may seem simple to just buy chicks, brood them for a month or six weeks and then release them into the coop with older hens. That’s not a good plan. Older birds don’t like the youngsters and harass them until a new pecking order is established. Sometimes old birds will even kill youngsters. To avoid this tragedy, we keep our old and young birds apart until the newbies are nearly fully grown at three to four months old.
Here is our general schedule:
- January: Decide how many chicks to buy in the spring and which older hens we will give away or sell for a nominal fee.
- March: Set up our chick brooder and buy chick starter feed. We then buy Hoover’s chicks from a local farm store or order them from the hatchery. Soon they’re basking in the brooder’s warmth.
- April: We place ads in social media announcing we have older hens to sell. Usually, buyers quickly emerge and about half our old flock is gone. (see a previous blog on how to downsize a flock).
- Late June to July. By now the babies don’t need brooder heat and have grown to half to two thirds of their adult size. It’s time to introduce the old and new birds.
The Double Coop System
We’ve made integrating old and young birds simpler by creating a double coop. All we actually did was build a plywood and wire screen wall separating the coop into two parts with a pop hole door between them. Our coop is fairly large so the wall is permanent, but people with smaller coops can create a temporary wall. Sometimes even a sheet of plywood can be made to work.
Just after half our flock goes to their new owner, we close the pop hole door between the two coops. One half holds the remaining older birds. We install the new partly grown chicks into the other half and keep them there until they’ve grown to nearly full size. That can take a couple of months. The double coop method means we continue to get eggs from the older birds until the young pullets begin laying.
Before we built our double coop we used an alternative system. We sold or gave away all our layers, thoroughly cleaned the coop, added new litter, and then raised newcomers there. It works but means there are several months without eggs
Integrating The Flock
Once our new birds are close to full size it’s time to let them mingle with the older hens. That’s best done after dark. We simply enter the coop with a flashlight and open the pop hole door as the birds sleep.
During the next few days, as old and young hens mingle, there’s plenty of pecking and chasing as an entirely new pecking order develops. It’s a stressful time for all the birds, but after a few days they all peacefully settle down and the flock becomes a combination of savvy old hens and somewhat naive new ones. As the older girls continue to lay the newbies gradually begin adding their gems to the nest.
Other Tips
Plenty of Space: Most chicken instructions advise giving large breed hens, like Rhode Island Reds, four square feet of coop space per bird and three-square feet for smaller breeds like Leghorns. Crowding creates aggression. The more space chickens have the more likely they will get along well. When mixing young birds with older established birds the transition is smoother and easier if the coop is spacious. Ours is about 100 square feet, shared by 15 birds, so each has about seven square feet. That’s not all. Every day they scamper around an outdoor run of over 2000 square feet. During the summer it’s filled with vegetation and shade structures. Our chickens love the run’s spaces that offer privacy and plenty of wild bugs, worms and plants to eat. Space reduces a flock’s social problems.
Body Size: It’s generally best to integrate breeds that have about the same adult size. We like trying different breeds but usually stick with heavy brown egg breeds. If we tried introducing smaller breeds, like Hamburgs, they might be dominated by the big girls. We also alternate with breeds easy to tell apart. For example, if our older birds have red feathers, we’re likely to buy new chicks that have black or white feathers or distinctive color patterns. It makes it easier to tell old birds from young ones.
To keep eggs constantly flowing from the coop to the chicken, replacing older hens is necessary. It can be done with minimal stress.











