Introducing new chickens to an established flock

Adding chickens to a flock you already have is the bit of chicken keeping most likely to go badly wrong, and the bit people most often rush.

Chickens are not welcoming. A flock is a settled hierarchy, and newcomers are an intrusion to be resolved by force. Done carelessly, introductions mean injured birds, birds too frightened to eat, and occasionally a death.

Done properly, it takes about four weeks and is completely uneventful. Here's the method.

Stage 1: quarantine, three weeks

Before the new birds go anywhere near yours, they need to be kept entirely separately for at least three weeks.

This is not about the pecking order. It's about disease.

New birds can carry mites, lice, worms and respiratory infections while looking completely healthy. Some carriers never show symptoms at all — mycoplasma is the classic example, and it can go through a whole flock. Three weeks is roughly how long most things take to declare themselves.

Quarantine properly:

• Separate housing, ideally out of sight and well away — different airspace if you can manage it.
• Deal with your own birds first each day, then the new ones. Never the other way round.
• Separate boots, or wash them between. Change or cover clothes.
• Separate feeders and drinkers, cleaned separately.
• Watch daily for sneezing, rattly breathing, bubbly or weeping eyes, diarrhoea, or a bird that's just quiet and hunched.

Use the time productively: worm them with a licensed poultry wormer, and check thoroughly for lice and mites — particularly around the vent and under the wings.

It is tempting to skip this, especially with birds from a reputable source. We'd urge you not to. The cost of getting it wrong is your entire flock, and mycoplasma in particular never really leaves.

Stage 2: see but don't touch, one week

This is the step that does most of the work, and the one people skip.

After quarantine, house the new birds where the existing flock can see them but not reach them — a wire panel between two runs, a dog crate inside the main run, a temporary pen alongside.

A week of this means all the posturing, staring and threat displays happen through a barrier where nobody can be hurt. By the time they actually meet, most of the argument has already been had.

Our rule of thumb: a week of mesh saves a fortnight of fighting.

Ten days is better than seven if you can stand the wait.

Stage 3: the introduction

Some principles that make an enormous difference:

Introduce at night

The oldest trick in poultry keeping, and it genuinely helps. Put the new birds on the perch after dark, once the flock has settled. Chickens are docile and largely inert in the dark, and waking up together takes some of the heat out of the first encounter.

It isn't magic — there'll still be a scuffle in the morning — but it takes the edge off. Be up early to watch what happens.

Never introduce a single bird

One newcomer absorbs the entire flock's attention and gets relentlessly targeted. Always add at least two, ideally three. They keep each other company and the aggression gets spread about.

If you've only got one bird to add, it's worth getting a companion for it rather than putting it in alone.

Match sizes if you possibly can

Point-of-lay birds into a flock of adults is manageable. Half-grown youngsters into a flock of adults is asking for trouble — they don't have the size to defend themselves and don't yet know the rules. Wait until they're near full size.

The reverse matters too: gentle heavy breeds like Brahmas often end up at the bottom regardless of size, simply because they won't fight back.

Change the furniture

Rearranging the run just before the introduction — moving feeders, adding a new perch, shifting the dust bath — disrupts the established territory and puts everyone slightly on the back foot. It sounds like folklore; it genuinely helps.

Space and escape routes

The single biggest predictor of a bad introduction is a cramped run.

You need more feeders and drinkers than usual, placed apart and out of sight of each other, so a dominant hen can't guard everything at once. And you need things to hide behind and get away from — pallets leant against a wall, a branch, a couple of boxes. A bird that can break line of sight can end a chase.

If you can, let them all out into the garden for the first meeting. Open space is far better than a confined run because the newcomers can simply leave.

What's normal, and what isn't

Normal, leave it alone:

• Chasing, pecking at the head and neck, hens standing tall and facing off.
• New birds keeping to themselves at the edge for several days.
• Squabbling at the feeder.
• New birds roosting apart, or refusing to go in the coop for a few nights — you may need to lift them in at dusk for a week.
• A dip in laying from everybody, including the established birds. Stress does this and it recovers.

Not normal, step in:

• Blood. Any blood at all. Chickens are drawn to red and will pile on a wound with real determination. Separate the injured bird at once, clean the wound, and use an anti-peck spray before returning it.
• A bird pinned in a corner and not allowed to leave.
• A bird unable to reach food or water for a whole day.
• Sustained attacks from several birds at once rather than one-to-one.

If you have to separate them, go back to the mesh stage for another week rather than trying again immediately.

How long it takes

Expect a fortnight of visible tension and about a month before they're a single flock. You'll often see the newcomers stick together as a sub-group for a good while — that's fine and it sorts itself out.

Laying usually resumes within a couple of weeks once things settle.

A word on cockerels

Introducing a cockerel to a flock that already has one is a different proposition entirely, and usually a bad idea unless you have a lot of space and plenty of hens. Two cockerels will fight, sometimes to serious injury.

If your flock is drifting male-heavy, that's its own problem — see too many roosters.

The short version

1. Three weeks quarantine, properly separate, your birds first each day.
2. One week seeing each other through mesh.
3. Introduce at night, at least two birds, after rearranging the run.
4. Extra feeders and hiding places, and more space than you think.
5. Intervene only for blood, or a bird being denied food or water.

It's four weeks of faff to avoid a problem that can cost you a bird. Worth it every time.