If you’ve owned a flock of chickens for any length of time, it will only be a little while before you start learning chicken math and then making additions to your flock. Pretty soon, a small backyard flock becomes six, then 10, then 15, and then who knows how many after that…

Chickens just take a hold on some people, and you can’t help yourself from getting more. But it’s a mistake to just buy some new birds and then throw them into the run or coop with your existing, established flock.

Chickens have a sophisticated flock hierarchy, or pecking order; they are downright tribal! If you don’t take the time to introduce new birds properly, your flock could turn on them and even kill them.

I know that’s the last thing you want, but the problem can be serious if you go about this willy-nilly. Keep reading, and I’ll tell you how to add new chickens to an existing flock with no issues.

Never Leave New Birds to Fend for Themselves!

If you learn nothing else from this article, learn this: you must never, ever dump a new bird in with your flock and then leave them to fend for themselves, sink, or swim.

If you do that, it’s a virtual certainty that the poor bird is going to be harassed and pecked quite literally to death. Worse, this sort of stress creates a domino effect, a social contagion, where other chickens will join in to bully the new bird to death, and then they might turn on each other.

It’s not as crazy as it sounds, and I’ve seen it before. No matter what kind of chicken, no matter how big your property, no matter what the size of your existing flock: follow these rules when introducing new birds.

Ground Rules for Introducing New Adult Chickens to Your Flock

Alleviate All Stressors

Before you even think of adding any new chickens, make it a point to eliminate all existing stressors. When the flock is stressed out, they will be on high alert and, let’s just say, less than welcoming to newcomers.

Make sure there isn’t already a problem with crowding and that they have plenty of room in the coop and in the run.

Also make sure they’ve all got plenty of food and lots of space around the places where they eat and drink. You don’t want them to be too hot or too cold, and make sure they’re getting plenty of good sleep at night.

If you’ve already relocated the tractor or moved them into a new coop, now is not the time to introduce new chickens. Wait until they acclimate. Similarly, if any birds are already recovering from illness or injury, it’s a bad time.

Assuming your flock is well-adjusted, happy, and healthy, then you can think about introducing some newcomers.

Isolate/Quarantine Newcomers

This is another commonly overlooked consideration when adding birds. No matter where you get them from, no matter how healthy they seem, you don’t want to take a chance with the health of your existing birds.

There’s no telling what sort of germs or parasites a new chicken might be hiding. Because of this, a quarantine or isolation protocol is a very wise idea for all new chickens.

Keep them well away from the existing coop and run for no less than 2 weeks and preferably for a whole month.

Make sure you check them for parasites during this time and, if necessary, get them a check-up with a vet. Some diseases have a long latent lifespan where carriers will show no outward symptoms, like certain kinds of bird flu and Mycoplasma gallisepticum.

Assuming they have a green light on health, you can proceed after the quarantine.

Never Add Just One New Chicken

Here’s another ground rule you would be smart to never break: you never want to add just one chicken to your existing flock. And I promise, this isn’t a quirk of chicken math…

The reason is that lone birds are disproportionately vulnerable to getting bullied by the entire flock, whereas if they have a little bit of backup, the attention of the flock will likely be spread out between them.

Hopefully, if they were raised together, the new additions will provide each other mutual support during what is often a troubling time.

Segregate Newcomers at First

So you’ve quarantined the joining birds, and several of them will be heading into the flock together. Don’t just dump them in the run and let everybody get to know each other. You still want to segregate the newcomers from the old hands.

Basically, you want the flock to see, hear, and smell the new birds but remain unable to get to them (for now).

This can be done by walling off part of the run using chicken wire or livestock panels, setting up an adjacent temporary run, or even using a large pet carrier or see-through playpen.

Whichever method you go with, make sure that the birds can’t reach each other and that you aren’t shrinking the existing run too much and causing a crowding problem which will only raise stress levels.

Plan on keeping your chickens segregated in this way for at least 7 days and preferably closer to 10 days. This, in my experience, is usually about how long it takes for the pronounced interest to fade within the flock.

Allow Newcomers to Mingle Once “Curiosity” Wears Off

Once the segregation period is over, it’s time to introduce your chickens to one another properly.

You can let them into the same run or other shared space, but make sure you’re observing them at all times for the near future, and also do the following:

Have a Perch for Newcomers to Retreat To

A raised perch in the form of a roosting bar, convenient branch, chicken swing, or something else that will allow your new additions to get up off the ground will be helpful.

Chickens that are attacked by other chickens and retreating will often look for a high place to retreat to.

Something about the psychology of these birds means that much of the time the attacking chicken will let them go and leave them alone once they are up off the ground.

Introduce Newcomers with Treats

Just like so many other social situations, when newcomers are joining an existing hierarchy, this period of uncertainty and transition can be lubricated with food.

Give your flock a big handful of their very favorite treats when you introduce the new birds, and let them get some too.

Although it’s not perfect, hopefully, this little bit of positive reinforcement will cement feelings of goodwill towards the new birds, but even if it doesn’t, the food will certainly distract them from getting too aggressive, at least for a while.

Expect Some Pecking Order Squabbles

Now, here’s the hard part…

No matter how diligent you are and no matter how docile your birds tend to be, there’s going to be some pecking, scuffling, and squabbling. That’s just the way it is, and that is indeed why it is called the pecking order, after all!

This is all a part of new birds being shown the ropes: who is the top bird and cock of the walk, which is the “assistant manager”, and so forth. This is why it’s so important for you to observe these initial interactions closely. Expect this “hazing” period to last anywhere from 1 to 3 weeks.

This pecking and pestering should not grow too serious or be relentless. If it is, or at the first sign of a legitimate injury, you must rescue the newcomer.

Consider Letting Birds Meet While Free-Ranging

If you have a large property, it’s a great idea to properly mingle your birds with one another outside of the run and far from the coop. This is very much a “neutral territory” thing and works well.

You can even keep this up for several days before allowing your new chickens to “go home”, as it were, to the run and coop with the existing flock.

Always Ensure Your Birds Settle Down in Coop

Ideally, you should never put new birds up with the flock in their coop unless they’ve been fully accepted – and you are sure of it.

But sometimes it’s hard to tell. In any case, you’d be wise to stick around and listen closely at the coop after all of your chickens retire for the night. This is to make sure there’s no squabbling or jockeying for position going on. They should settle down, settle in, and go to sleep quickly.

If they won’t, and if the newcomer is either making waves or the subject of harassment, you’ll need to remove them and put them in their own coop for the time being. This could be something as simple as a pet carrier if needed.

Watch Out for Cannibalism!

One more thing to be aware of when introducing new chickens is that their presence can spark an outbreak of cannibalism in your flock. No, this isn’t some exaggeration.

When chickens peck and harass another bird and draw blood, they might inflict severe injuries and eventually kill them. If this happens, the interloper is often eaten, at least partially.

Worse, it seems some chickens actively develop a taste for blood and then might start turning on one another. Like I said above, this is a kind of social contagion and one that you must prevent and nip in the bud at all costs.

If you notice any of your new birds being relentlessly bullied or injured in any way, you must remove them and calm the flock down as quickly as you can.

At What Age to Introduce Chicks

It is critical that you give young chicks plenty of time to develop into adolescents prior to introducing them to the flock.

You should not attempt to introduce them any earlier than their 15th week of life. Once they have nearly all of their adult plumage, they are ready.

Note that chickens that have not yet developed their adult feathers, or ones that are still growing sparsely, are highly likely to be targeted for bullying.

How to Introduce Young Chicks

Don’t. This is a recipe for disaster. The only exception is if chicks are born and cared for by a diligent, broody hen in the coop where the flock sleeps. In such cases, the mom will keep the chicks safe and the rest of the flock in line concerning their treatment.

In all other cases, wait until the chicks have developed enough to pass as adults and then begin integration.

However, it can be helpful to keep baby chicks near the run or coop when going outside during development so the flock can see, hear, and smell them. This can facilitate integration when they are older as detailed above.

Best Age to Introduce New Adult Chickens

You can add mature, adult chickens to an existing flock at any age, but there are some additional dynamics to keep in mind.

Younger adult birds are generally more tolerant of the youthful enthusiasm of younger chickens. Conversely, old birds entering their golden years usually have less energy and less tolerance for new kids on the block. ?

Overloading a senior flock with too many new youngbloods is bound to increase stress levels more than it would usually.

Can You Add a New Rooster to an Existing Flock?

You can, but think twice. If your flock already has a rooster and you add a second one, they are going to fight to establish dominance over one another, and these fights can be very serious.

Roosters that grow up together will often establish their own command hierarchy but it is somewhat distinct from the flock hierarchy. But in the case of an interloper, meaning your new addition, both birds will fight tooth and claw – and may even do it to the death!

Maiming and severe injuries are likely outcomes. And for what? Just because you want another rooster? It might not be wise. If you have to have more roosters for whatever reason, you’re probably smart to put them in their own rooster colony separate from the flock.

Other Considerations

Number of Newcomers

It’s always good to introduce more than one new chicken at a time to your flock, but don’t overdo it, either. If you add what’s basically an entirely separate flock to the one you’ve already got, that can lead to war and even if it doesn’t, stress levels will go through the roof.

Generally, I like to maintain a ratio that is about three or four to one of existing birds to newcomers at any given time.

Temperament of Existing Birds

Something else you should keep in mind at all times is the temperament of the breeds in your flock already. Game breeds are notoriously unaccepting of outsiders.

That being said, chickens are individuals to one degree or another, and if you’ve been spending time with and observing your flock, you should already know who the prime suspects are going to be when it comes to bullying.

Be prepared to react accordingly when you finally get around to introducing the new additions.

Likeness of Newcomers to Existing Flock

I know it’s something that people don’t want to consider, but chickens really do prefer their own kind.

Chickens of any breed prefer their own breed, prefer their blood relatives, and even show a marked preference for chickens that are the same color as them.

The greater difference, or variation, there’s between the baseline of the flock and the arriving chickens, the more likely it is they will be severely bullied.

On the other hand, if you’ve already successfully raised a mixed flock, usually done when they are all chicks, you are less likely to have problems owing to diversity.

Size Disparity

Another big consideration that can have big consequences if not managed properly. Bigger birds tend to rule the roost across all circumstances.

If you have a huge bird, and particularly a huge rooster, like a Leghorn, Malay, Jersey Giant, or similar, and introduce a little bantam breed, that can turn fatal before you can react.

“Reverse” Introduction

If you have an unruly flock and are trying to introduce particularly docile chickens, you’ll probably have better results doing a reverse introduction.

Using this technique, you’ll set up the newcomers in their own run and coop, and after the quarantine is over, you’ll bring one or perhaps two birds at a time from the existing flock to meet them.

This changes the power dynamics as you might imagine, and while not always successful, it prevents the snowball effect that always occurs when one bird decides to jump the new chickens which leads to a swarm of pecking and bullying.

If that goes well, you can slowly migrate the existing flock one or two members at a time to the new flock until everyone is together and living harmoniously.

Use Peepers for One or Two Troublemakers

Every now and then you’ll get lucky and only have one or two birds in your flock that seem to be giving newcomers problems.

As mentioned above, you can’t let this go on because it has a way of becoming contagious. That being said, if you are so close to achieving integration, it’s worth taking direct action against the troublemakers.

The best way to do this is by fitting them with peepers, also known as blinders.

Working similarly to the blinders that racing horses wear, these specialized pieces of chicken headwear prevent chickens from seeing directly ahead of them though they can still see to the sides. Not much of a blinder, right?

As it turns out, aggressive chickens are only really likely to attack the targeted bird if they can see it directly in front of them. If they see it off to one side or the other, they typically won’t do it.

It’s a neat trick, and a good way to restore order without hurting or exiling the aggressive birds. Given enough time, they should settle down and then you can remove the blinders and try or quickly refit them if they relapse.