How to integrate new hens in an existing flock


Adding pullets (or adult hens) to an existing flock is a very delicate exercise. It must be done with great care and attention. Here biosecurity, isolation and integration must be well understood by all those trying to integrate hens. From the outset, all forms of animal cruelty and unnecessary stress must be avoided.  The old methods of odour camouflage and night-time entry should be completely banned. These methods have evolved and are now supported by research and science.  In this article, I will share with you the best practices to put in place so that this experience is as pleasant for you as it is for your chickens!

Have you heard of the term (Pecking Order) hierarchical order? This term, which is even used with humans, derives from the behaviour of chickens. Hens peck other hens to demonstrate dominance and ranking order in the group. As hens have always lived in small groups in nature, order and hierarchy are very important and each hen has to know its rank, place and status. Each pool will have a different reaction to newcomers. Some will be more accommodating and almost indifferent while others will be intolerant, ruthless and may attack and injure intruders to death. 

Even your sweetest, easy-going hen will become more aggressive and may peck a newcomer in her territory. This is only natural, as rank and order need to be re-established and it can take time to establish the new balance in the new group. If a hen’s rank is at its lowest and she dares to eat first, others will look at her and say, “What do you think you’re doing? Take your place and wait your turn! I am more senior than you are here. 

After thousands of years of evolution, chickens have learned to avoid bickering over food and have developed this system to avoid attracting the attention of predators. When I say that the term pecking order is also used with humans, think of high school or a teenager (or a group of teenagers) showing their dominance to others by being mean and not allowing them to hang out with them, not wanting strangers sitting at their table at dinner, etc. It’s peckish! (Pecking order). A flock of existing chickens will have become accustomed to their environment and have established “friends” to walk around with them. They also have a leader in place.

Adding young beginner hens or older hens throws the order out of balance. Our chickens are very sensitive beings and do not have a very good capacity to adapt to change. It takes them time. Our current flock will be stressed and may have surprising reactions, especially if you introduce hens of different breeds they have never seen before!  In order to limit the stress and facilitate the integration, the introduction of new hens must be done with a lot of care.  It is an experience that might be difficult for humans to overcome, as witnessing hens pecking and attacking each other is not pleasant to see, but after a few weeks we must let them do it.   

So, while there are many methods and opinions may vary, here I share with you some techniques and best practices to facilitate this transition.  The secret to a successful transition is time and patience, as the whole process could take 6 to 12 weeks. Four weeks of quarantine, one to three weeks of segregation and isolation, one to three weeks of acclimatization and finally integration of one to four weeks.  

Did you know that hens’ sense of smell is not as developed as that of mammals? Sight is the most developed sense.  Forced integrations can give us the impression that things are going well, but be aware that severe aggression reactions may occur later in time. Just because in the first week everything seems to go well from your point of view, does not mean that the order of rank and hierarchy is well established. Reactions of incessant pecking, aggression, egg drop and disease occur later and the damage is done. It will always be difficult to bring harmony back into the flock.

First step: 30-day isolation

To avoid disease transmission, it is important to keep our new hens in a separate cage or henhouse for at least 30 days.  Make sure that the temperature is adequate for their age. At this stage they are under observation. Even if they seem perfectly normal and healthy, many hen owners have had to destroy and eliminate their entire flock of hens after bringing in a serious disease such as Newcastle disease, Mycoplasma gallisepticum mycoplasmosis, infectious laryngotracheitis, avian influenza, Marek’s disease or other contagious and sometimes asymptomatic disease in several carriers!  Very often, chicken dealers do not know that their hens are carriers of diseases!  Vaccination is recommended for all chicks in order to avoid serious diseases, bacterial complications and the use of antibiotics.

The isolation period also allows us to treat sick hens and avoid spreading these diseases to our existing flock. Always have good hygiene practices and wash your hands after each handling so that you are not the vector of diseases in your flock! Some pathogens are carried in the air, others through your clothes and shoes! Change your shoes and wash your hands regularly before touching your chickens and poultry house.

Some chickens will be so stressed that they may have some diarrhea. The use of natural yogurt is a perfect probiotic for our chickens. Apple cider vinegar in water and vitamins will be welcome to help them through this ordeal. Stress could cause them to lose feathers, so increasing protein intake will help them.

Make sure that the new hens are comfortable and can still benefit from all the advantages of your flock. But don’t let them out on your property yet. Watch the crest, legs for scabies, lice, worms, and eyes. Make sure breathing is normal and that no cold snorts or runny noses are present. If you detect a serious illness, most experts suggest removing these chickens. This may sound harsh, but it’s better to remove a weak and sick hen than to have the entire flock affected and have to exterminate it.

Step 2: Segregation and separation (we see each other, but don’t touch)

When the isolation period is over, you can introduce your new hens in a separate part of your poultry house for a few weeks.  Having wire mesh or space dividers is handy at this stage.  Sometimes, you can use mini-enclosures such as Mcmurray hatchery’s Peck and Play net pen or other types of animal enclosures and place the new hens away from other hens. The new hens will begin to get used to their presence and spend time around them without being able to intimidate them.

Make sure they are protected from heat stroke by providing shade and that food and water are in place in each group.  At this stage, your hens will be curious, watching the new hens without being able to touch them.  Curious, they may growl while making a lap around the cage.


Step 3: Acclimatization

After about 10 days, approach tests can be started.  For example, you could leave them together for a few minutes several times a day.  Don’t be fooled by your beautiful, sweet and beloved chick, as she might show you her worst temper.  Often the older chickens are the most dominant.  You may see dramatic behaviour such as a grunt of discontent for example, jostling and chest bumping.  I advise you that this whole merry-go-round is not pretty but necessary.  Place containers of food and water in several places.  You will have to watch this step carefully and separate chickens with inappropriate behaviour.  Transfer your chickens to different areas and let the new hens explore the barn at their ease.

On certain days, you can isolate the old hens in the tunnel enclosure or the Peck and Play pen for a few hours and let the new hens spend time in the henhouse feeling the environment, eating and drinking and especially getting familiar with their surroundings.   They must take their place and be able to integrate the group.  Pecking will be unavoidable and necessary, but bloodshed or serious injuries must be avoided.  For us humans, it may seem cruel to see all this behaviour, but I assure you that pecking is not always hurtful.

Step 4: Integration

When you feel that your chickens are finally ready to settle in, you could tuck them in the evening with the others in the dormitory and so they will sleep together.  But the next morning, as soon as the sun’s rays come out, take them out, as there might be a fight in the dormitory.  However, they might also wake up and say, ah, new friends and not be too fussy.  One trick during the day is to bring distractions, treats such as fresh grass, a piece of cabbage or other attractions.  

Cautionary note:

  • Do not introduce a new rooster into a group that already has a rooster that has established its territory;
  • Do not introduce chicks to a group of mature hens. Mature hens could kill your chicks.
  • As far as possible, do not introduce a single hen on its own into a new group. She will be helpless in the group being the newest, she will be alone and this will cause her a lot of stress and could cause her to die. Ideally, you want to introduce at least two hens at a time.

Make sure that your new chickens can go and hide somewhere in a corner of the pen in case of a severe attack.  Beware of commercial or online mini henhouses, almost all of which are inadequate to house our hens and unable to provide the minimum space required.   Monitor the dynamics and if one of your hens becomes extremely aggressive, take it out of the group and isolate it.  Keep a close watch on your new hens and any injuries and especially blood sores.  Because if a hen starts to lose feathers, and a wound is revealed, all the hens will peck it.  So take her out of the group and isolate her.  Use a disinfectant spray on wounds like (Vetericyn Poultry care) and then use a product that helps reduce pecking. 

Your chickens will be able to show superior behaviour by ruffling their feathers and blocking the passage and access to food.  After a while, they will restore order and eventually find their own comfort zone in the group.  Note that your new chickens will tend to stay close together.  By coming together in this way, they will be more confident with the rest of the group.  Eventually, you will see harmony set in and your new chickens will finally be integrated.  All’s well that ends well.

Good integration!

For more information, visit the EQCMA website where information on backyard animal husbandry is available.

By-law respecting the containment of captive birds,%20r.%204

Animal Welfare By-law

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