Introducing New Chickens to a Flock: A Practical UK Guide

Adding a few new hens is one of the nicest ways to grow a backyard flock, but chickens don’t welcome strangers. Put new birds straight in with a settled group and you risk bullying, injuries and, worse, bringing in mites, worms or illness that your own birds have never met. The good news is that introducing new chickens to a flock goes smoothly most of the time if you slow it down and plan the space.

This guide walks UK keepers through it step by step: quarantine, a see-but-don’t-touch stage, the first meeting and the first fortnight. It’s practical husbandry advice, not veterinary advice, so if a bird looks unwell at any point, speak to a poultry-experienced vet. If you’re still choosing birds, read our checklist for buying chickens in the UK, or browse chickens for sale on The Eggschange.

Before you buy: plan the numbers and the space

The single biggest thing you can do happens before the new birds arrive. A lone newcomer takes all the attention from the whole flock, so never add just one hen. The British Hen Welfare Trust advises giving the new birds the advantage in numbers where you can, for example adding six hens to a flock of four, and not taking on extra birds if a small coop and run leave no room to keep the groups apart.

Check the coop and run will cope with the bigger flock: perch space for everyone, enough nest boxes and enough ground for a low-ranking hen to keep out of trouble. Try to add birds of a similar size, as bantams and large fowl, or young pullets and mature hens, are harder to mix safely. Our guide to point-of-lay hens vs rearing chicks covers how the age you buy at changes the plan.

Step 1: quarantine new birds first

Birds from sales, markets and other keepers can carry parasites or infections without looking ill. Keeping them completely separate for a while gives anything they’re carrying time to show. Advice varies on how long: the British Hen Welfare Trust suggests around a week to ten days, while the NADIS poultry biosecurity guidance suggests two to three weeks for new stock. Longer is safer if you have the space.

During quarantine:

• House the new birds in their own coop and run, away from your flock, with separate feeders and drinkers.
• Look after your existing flock first and the new birds last, and wash your hands and change or clean your boots between the two.
• Watch appetite, droppings and breathing every day, and check under the feathers around the vent for mites and lice. Our guide to spotting mites and lice shows what to look for.
• Listen for sneezing, rattly breathing or bubbly eyes. See early respiratory signs in backyard chickens, and call a vet rather than guessing if you’re worried.
• Think about worming and parasite treatment for the whole flock around the time you merge. Our chicken worming basics guide explains the options, and a vet can advise on products.

Step 2: let them see each other before they meet

Once quarantine is over and everyone looks healthy, move the newcomers somewhere the two groups can see and hear each other but can’t touch: a run divided with mesh, or two runs side by side. A week or so of this lets the existing flock get used to the new faces, and the first squabbles happen through the wire rather than beak to beak.

If you can, the British Hen Welfare Trust suggests putting the new birds in the main long-term housing and moving the established hens to a temporary run for a few days, so the newcomers learn their permanent home and its hiding places first.

Step 3: the first meeting on neutral ground

Chickens defend territory they know, so a first meeting somewhere new to both groups is calmer. A fresh patch of garden works, and some keepers move the coop and run to a different spot before merging so neither group has the home advantage.

• Start with short, supervised sessions and stretch them out over several days.
• Late afternoon helps. The British Hen Welfare Trust suggests merging about an hour before dusk, when birds are thinking about bed rather than arguments.
• Put out several feeders and drinkers, spaced apart, so no hen can guard them all.
• Add things to hide behind and perch on: a pallet leaned against the fence, a stump, a low branch.
• Scatter some greens or hang a cabbage to give everyone something else to do.

Another common method, once the newcomers are settled in the permanent house, is to place the established hens into the coop quietly at night. Whichever you choose, let them out at first light so trouble doesn’t start in a crowded house. In summer, the British Hen Welfare Trust suggests blacking out coop windows so the birds don’t wake before you’re up.

What normal pecking order behaviour looks like

Some chasing, pecking and posturing is normal. The flock is working out a new pecking order and you can’t skip it. Expect birds to be pushed off the best perch or away from the feeder for a while. According to the British Hen Welfare Trust, squabbling usually settles within a few days, and merging problems should resolve within about two weeks.

Step in and separate birds again if you see:

• blood on a comb, wattle or anywhere else (chickens are drawn to peck at red, so a small wound can get worse quickly)
• a bird being pinned down or chased relentlessly with nowhere to escape
• a hen hiding all day and not eating or drinking
• one bird ganging up on newcomers long after the others have settled

Keep an injured bird apart until it has healed, and ask a vet about any wound that looks deep or doesn’t improve. Then go back a step to the see-but-don’t-touch stage and try again more slowly.

Paperwork: is your flock registered?

In England and Wales, anyone keeping poultry must register with the Animal and Plant Health Agency (APHA) within one month of keeping them, even a few garden hens kept as pets. GOV.UK’s guidance (updated 30 September 2026) says you don’t need to update your record just because the number of birds changes while you still have fewer than 50. You do need to tell APHA within 30 days if other details change, such as the species you keep, or if you start keeping 50 or more. Scotland has its own Scottish Kept Birds Register. Registering also means APHA can contact you if there’s a bird flu outbreak near you.

Quick checklist for adding new chickens

• Add at least two birds, ideally similar in size, and plan the numbers so newcomers aren’t heavily outnumbered.
• Check perches, nest boxes and run space for the bigger flock.
• Quarantine new birds separately and watch them every day.
• Give a week or so of see-but-don’t-touch through mesh.
• Merge on neutral ground, late in the day, with extra feeders, drinkers and hiding places.
• Expect a few days of squabbling, step in if there’s blood or a bird can’t eat, and see a vet for injuries or illness.
• Make sure your flock is registered with APHA.

Finding new hens on The Eggschange

The Eggschange is a UK classifieds marketplace for hatching eggs, chicks, chickens and poultry equipment. You can browse current listings for point-of-lay hens, spare coops and runs to use for quarantine, or place a listing if you have birds or kit to rehome. Listings cost £1 for 90 days. See how The Eggschange works, read more in our poultry guides, or contact us if you have a question.