How to Introduce New Hens to an Existing Flock

Bringing new hens into an existing flock is one of the riskiest moments in backyard hen keeping. Hens have a pecking order, and newcomers are strangers. The safe approach is to slow the whole thing down: check the new birds over before they come home, keep them separate but in sight and sound of your flock for a week to ten days, then merge them gradually at dusk when birds are more interested in roosting than fighting¹.

Two rules matter more than any other. First, keep new hens separate from your existing birds for at least a few weeks if they are rehomed commercial hens, because they may be unfit and easily bullied at first³. Second, never feed kitchen scraps to chickens, which is illegal because of the risk of disease⁴.

This page covers what to check before you bring hens home, how to set up space and quarantine, how to merge the flocks, how to feed a mixed flock, and what to watch for in the weeks afterwards.

Check new hens are healthy before you bring them home

Before any hen crosses your threshold, look her over. The advice for all hen keepers is to check your flock regularly and handle your birds often enough that you know when one is feeling poorly⁸. A healthy hen should be busy and active, scratching the ground, feeding and drinking well (though not excessively) and preening⁸. A bird that sits hunched, ignores food or stands apart is telling you something.

If you are rehoming ex-commercial hens, expect them to be in poor condition at first. They may have never perched, never seen grass, and never had to find shelter. Very often they will sleep on the floor of the house initially, though colony hens who have had access to low perches adapt quickly, and free-range and barn hens will have no problem perching⁹.

Ask where the birds came from. Hens from auctions, markets and hobby breeders are unlikely to have been vaccinated, which makes the separation period an important quarantine time¹. Caged hens, by contrast, are unlikely to have worms at the point of adoption as they have had no contact with solid ground¹⁰.

If you keep a cockerel, supervise introductions between him and new hens closely to make sure the hens do not suffer injuries³. The same applies to dogs: do not leave hens unsupervised with a dog until you are satisfied the dog is hen friendly³.

Keeping at least two chickens, and making space in the coop and run

Space is the quiet factor that decides whether a merge goes smoothly or turns into persistent bullying. Chickens are social creatures, and a minimum of three hens in a flock is recommended⁶. If you are adding to an existing group, the British Hen Welfare Trust advises adopting a greater number of hens than you currently keep: if you already have three hens, adopt at least four new ones so the incoming birds have the advantage in numbers⁵.

Coop sizing is often overstated by manufacturers. For a coop sold as housing three to five hens, the Trust would recommend it is suitable for three ex-commercial hens¹¹. Plan for the lower end of any range.

When hens first arrive, there should be some kind of enclosure around the coop so they become "homed" and learn where to eat, drink and go to bed, meeting minimum spacing requirements to reduce stress or bullying¹¹. Put them in the hen house initially so they get accustomed to where home is, but allow them outside access straight away provided you have a fenced area⁵. If you have a small enclosed run, leave the door or pop-hole open; if there is no enclosure, make sure the hens are secure and cannot wander off⁹.

You may need to help them understand their new daily routine by encouraging them out in the morning and ensuring they are tucked up ready for bed in the evenings⁹. For more on housing, feeding and the law, see Keeping Chickens, and for space figures in detail, How Much Coop and Run Space Do Hens Need?.

Merge the flocks slowly, and at dusk

The merge itself should be a staged process, not a single release. Start with a "see but no touch" introduction: bring the new chickens into view of your existing flock, which also acts as a quarantine period⁴. Then let the chickens share the same space for short times over a few days, doing so at dusk when they are more focused on roosting than fighting, and increase the time gradually⁵.

Some dominance behaviour is normal while the pecking order is being established. What is not normal is bullying that breaks skin: separate the birds if this happens¹². In summer, black out the coop windows with a black plastic bag so bullying does not start before you are up¹².

If you are introducing birds at night, place the new chickens in the house with the flock when they have gone in to roost, then let them all out in the morning and keep an eye on them¹³.

Practical remedies for a bullied hen include smearing Vaseline on the combs of the bullied birds, so bullies cannot get a grip; putting several sources of food and water in the pen; hanging distractions such as shiny CDs, half cabbages or corn on the cobs just above head height; and giving enough space that the lowest ranking hen can stay out of trouble⁵.

Feeding a mixed flock: grit, oyster shell and no kitchen scraps

A mixed flock of old and new hens needs one ration that suits all of them. Chickens do not have teeth, so they need insoluble grit, such as hard flint grit, to grind and digest food. They also need oyster shell as a soluble grit providing extra calcium, particularly important for laying hens for stronger eggshells⁴.

It is illegal to feed kitchen scraps to your chickens because of the risk of disease⁴. A small amount of mixed corn in the afternoon is fine, but do not overfeed with treats or scatter food on the ground, as this will attract mice and rats and may adversely affect egg production⁵.

In winter, a little cod liver oil can be added to the ration, and wheat and maize can be offered as a scratch feed to keep the birds active¹⁴. Hens will eat more in colder months to generate body heat, and they sleep more in winter to conserve energy, so they are generally less active during the day⁶. For daily quantities, see How Much Food Does a Hen Need Each Day?.

Watch new and existing hens for signs of illness or heat stress

Spend a bit of time watching your hens each day and you will quickly learn their normal behaviour, so you can spot when one is out of sorts². Stress, for example from moving to a new environment, can disturb a hen's immune system so worms breed wildly and affect health, so monitor the worm burden: any bird off its food or moping is suspect¹⁰. For more on common problems, see Chicken Health.

Heat is a real risk in summer, particularly for a new bird that does not know where the shade is. Watch for early signs of heatstroke, such as heavy panting, restlessness and lack of coordination¹⁶. A fast heartbeat is another symptom¹⁷. If you have any concerns about an animal's health, contact a vet immediately¹⁸.

Red mite is another hazard worth checking for when birds are stressed or crowded. Diatomaceous earth products are described as safe to use for hens and people alike; dust newly purchased birds directly onto their bodies, working the powder through the feathers before merging them into your flock¹⁹.

If a hen goes broody, lift her out, take her to food and water, and try to keep her out of the box for increasingly longer periods²⁰. For handling at night, practise in the dark with a very dim torch when the hens should be on their perch, move quietly and slowly, talk to them all the time, then pick one hen off the perch with both hands around her wings and body, facing towards you²¹.

Avian Influenza Prevention Zone: don't handle sick or dead birds

An Avian Influenza Prevention Zone is currently in place across the UK, and it changes what you should do around sick or dead birds⁶. Do not touch or handle sick or dead birds. If you have to, thoroughly wash your hands immediately afterwards, keeping them away from your face or food²².

The same warning applies to anyone keeping ducks or geese²³. Official guidance is blunt: do not touch or pick up a dead or visibly sick wild bird²⁴.

Biosecurity precautions under the zone include cleansing and disinfecting equipment, vehicles and footwear; storing feed, water and bedding undercover; effective vermin control; keeping birds in a fenced-off area so they cannot access standing water; regularly disinfecting the coop and run; and discouraging wild birds from entering the area⁷. If a Protection Zone is declared, hens must be housed, increased biosecurity measures must be taken, anything that may be contaminated must be disinfected immediately after transportation, and you must keep a record of anyone who visits your home and has contact with your poultry⁷.

In all disease control zones you must follow biosecurity rules, keep a record of anyone who transports or markets poultry or poultry eggs (with exemptions for table eggs), follow rules for fresh meat, comply with biosecurity rules imposed by a veterinary inspector, not organise or attend bird gatherings, and not release game birds²⁵.

To report dead wild birds in Northern Ireland, use the DAERA Dead Wild Bird online reporting tool²⁶. In Great Britain, report to Defra if you find one or more dead birds of prey, three or more dead gulls or wild waterfowl (swans, geese and ducks), or five or more dead birds of any species²⁵. For day-to-day routines, see Daily Biosecurity for Backyard Poultry Keepers.

When a poultry-friendly vet should see your hens

Most settling-in problems resolve with time, space and good feed. Some need a vet. Any bird that is off its food, moping, or showing the heat stress signs above should be assessed, and if you have any concerns about an animal's health, contact a vet immediately¹⁸.

Worms are worth understanding because stress and moving make them more likely. Monitor the worm burden, and treat any bird off its food or moping as suspect¹⁵. If you are unsure whether a hen is broody, ill or simply low in the pecking order, a poultry-friendly vet can tell the difference.

For newly adopted ex-commercial hens, the first days are the vulnerable ones. Ex-commercial hens may need physically picking up and put under shelter for the first day or two if the weather is bad, and lifted into their hen house at bedtime²⁸. Initially hens will not know how to shelter and may stand outside when it is wet and windy, so you may need to physically put them in the coop if the weather is inclement⁵.

If you are bringing home rescue birds, the Checklist for Bringing Home Rescue Hens and Looking After Newly Adopted Ex-Battery Hens walk through the first days in order. For the wider picture of keeping hens at home, start with Self-Reliance at Home.