Chicken Health



All pets need to be carefully looked after to avoid health issues. Chickens, like dogs, cats, horses etc can acquire internal parasites (worms) and external parasites (lice, fleas and mites). They are also susceptible to some bacterial and viral infections.


Your chickens will have been vaccinated before purchase but this alone will not ensure they are completely free from disease for the rest of their lives. Good hygiene, good food and good animal husbandry are important.


Most health issues can be kept at bay by completely isolating your chickens from all other birds. In a back yard this is not practical and probably not possible; it would require the absence of all other bird species, wild and pet, within a large radius of your home. Even then there is potential for disease to be transmitted through the air or on shoes from outside of your property.


By quarantining any new chickens to your flock for a few days and closely observing them you will allow time for your pets immune system to adjust to their new home and reduce the risk of stress-induced illness from changing environments.  It is possible that existing chickens on your property may be carriers of a disease but not showing any outward signs; when you introduce your new chickens that have not been exposed to that particular disease, and are stressed from moving home (who enjoys moving house?), the latent disease may affect them.


Actively observe your chooks every time you see them; even those new to the wonderful world of chickens will soon be able to detect an unwell bird if they pay attention to their comb colour, gait, breathing, food intake, droppings and socialisation with the other chickens.  Often the first sign people notice of ill heath is a chicken that is isolating herself from her flock or a drop in egg production.


Signs you may observe.

Drop in egg production.

The number of eggs produced by a hen is influenced by genes, ambient temperature, daylight hours and health.

Some breeds of chickens lay more eggs than others so concerns over the number of eggs produced should factor this in.

Very hot weather can cause a reduction in the amount of eggs your chickens lay; ensure they have plenty of fresh, cool water and good ventilation in the nest area as well as shady areas for them to avoid the heat.

The length of a day, sunrise to sunset, causes the biggest impact on egg production. As daylight hours reduce so too will egg numbers with most breeds ceasing to lay completely for a short time. This is a natural occurrence but after winter solstice (June 21st or 22nd), as daylight hours increase, your chickens should start to lay more productively again.

An unwell chicken will not lay to her best ability, even a mild illness can impact egg production for several weeks.


Feather loss.

‘Moth eaten’ chickens or bald patches are most commonly caused by an over amorous rooster, external parasites, feather picking or moult. 

Roosters will cause feather loss on the back of the hen’s head where he grips with his beak and on her lower back as he ‘treads’ her during mating.  

Parasites can cause feather loss anywhere as they irritate the chicken and she will scratch to try to remove them. 

Feather picking often starts when chicks are very young under heat lamps.  The chicks or older chickens will peck at the soft downy feathers of other birds, continuing until bald patches appear. When pin feathers follow they too are pecked out; this can become habitual and so very hard to eradicate. It is often attributed to boredom although even chickens that are provided with environmental enrichment will still feather pick.  Some breeds are more at risk for this behaviour.

Moulting usually coincides with cessation of laying during the shorter daylight hours.  The feathers fall out leaving the chickens almost bald in some cases but new ‘pin’ feathers will soon start to show through followed by a lovely new coat of feathers.

All the above causes of feather loss are either transient or can be rectified and your chickens should soon be in full feather again.


External parasites. 

Lice, mites and occasionally fleas can infest your chickens causing irritation, feather loss and in severe cases ill health possibly leading to death. But it is possible for a chicken to be heavily infested and not show obvious signs so close physical inspection should be performed regularly looking at the skin under the feathers especially around the vent, under the wings and on top of the head in crested breeds.

Lice are creamy white to tan and and about 3mm long. They may crawl onto you when handling your infested chickens but they will not stay long as they are very species specific. Lice will only feed on the one host type; i.e. poultry lice feed on the dander (dead skin) of chickens, horse lice feed on horses, goat lice feed on goats. 

Chickens are susceptible to two mites; the Northern Fowl Mite which lives on the chicken and will also crawl onto you if the chicken is heavily infested and the Red Mite which feeds on the chicken at night then leaves to nest and reproduce in cracks and crevices in the hen house. It can survive for up to 8 months in the environment and is happy to feed on people too causing nasty irritations. Ensuring your coop is clean, your chickens have access to dust baths and are inspected regularly and treated promptly if there is evidence of parasites is the easiest way to avoid heavy infestations and problems for yourself. Heavy infestations can be hard to eradicate. It requires treating every chicken, completely emptying the coop of all litter and bedding and, in most cases, spraying with insecticides. Prevention is far better than cure!


Internal parasites.  

Commonly known as worms, internal parasites infest most chickens particularly when they free range. There are several types of internal worms but in small numbers most do not cause problems in a healthy chicken although with heavy worm burdens chickens can become very ill. To ensure your chickens aren’t heavily infested it is good husbandry to worm them regularly with a good quality poultry wormer. A commonly accepted regime is every three months at the start of each new season. Please note that some preparations may be passed, in minute amounts, into the eggs for a short while so please abide by any withholding periods (time that the eggs are not suitable for human consumption) on the product you use.



Chickens like to create a ‘pecking order’ and in so doing will often have small wounds particularly to their comb.  The comb has a good blood supply so the wound may bleed freely but in most cases will generally heal well without any treatment. But be aware that chickens are attracted to red and when they see blood they will often peck at it causing further damage or at least delay healing. If you notice any wounds that look blistered at all or have pus please take your chicken to an avian vet to rule out anything sinister; e.g. fowl pox which is highly contagious.


Keeping Them Healthy


Food quality.

Chickens can survive on scraps, scratchings and foraging but… humans can survive on junk food!  When in peak egg laying production a junk food diet is not enough to sustain the energy requirements that go into egg laying.  Wild chickens who only forage and still lay eggs are healthy but bear in mind that they lay far fewer eggs than domestic chickens do. There are many high quality chicken feeds available in pellets, grains or a mix of both. Feed your chickens the best quality food you can afford, after all, they are feeding you with their lovely fresh eggs. 

It is also important to feed them an age appropriate diet. Starter crumbs are too fattening for adults and adult diets lack the fats and protein required for growth in younger chickens. Also, perhaps more importantly, most better quality starter crumbs and growth diets contain a coccidiostat.  Coccidia is a parasite of the intestinal tract that is not treated by worming.  It is very common in the environment and most chickens will develop immunity to it but until they do they are very susceptible and in severe cases coccidiosis may cause death.  The most common sign first noticed by owners is blood in the faeces.  If the chicks are fed a food containing a coccidiostat they are much less likely to develop coccidiosis.

Let them forage if possible too, this is a great supplement to their diet and will help rid your garden of snails and grubs.

Kitchen scraps are great and add variety to their diet, particularly if they do not free range but ensure there is no rot or mould on any scraps. Meat and bones are fine to feed your chickens as they are omnivores but bear in mind that these will also attract foxes, even in inner city areas.



If chickens lack water for just a few hours you will see an almost immediate reduction in the numbers of eggs produced. Eggs have a lot of water content so chickens must have access to plenty of fresh, cool, clean water. A fixed container that cannot be tipped over and preferably that self fills with a shut off valve is ideal. It needs to be deep enough that water remains cool but not so deep that young chickens are at risk of drowning.  Place it in the shade, clean it often and check regularly for leaks.


Complimentary Medications.

Apple cider vinegar has long been touted as a cure all for all sorts of maladies including worms.  While it does have some benefits in small doses it can be harmful if too much is given although most chickens won’t freely drink a dangerous amount. It is contraindicated in sour crop though where the contents of the crop are already acidic.

Diatomaceous earth is increasing in popularity. It is best used in poultry as an aid in eradicating external parasites. It can be dusted directly onto your birds, onto their perches and incorporated in their dust baths. It is made from powdered shells and is abrasive to the shells (skin) of the parasites. For this reason it is probably best not to feed it to your chickens although many sites claim that it is good at eradicating intestinal worms. 


In summary…

Quarantining sick birds and observing them closely, providing plenty of fresh water and soft, easily digested foods; e.g. boiled white rice, may be all that is required but if they are not improving fairly quickly or are worsening or if more chickens are becoming affected then they need veterinary care. This is not the place to discuss or diagnose health problems; diagnosis of a health problem can rarely be accurate without a hands and eyes on examination. Keep the number of a good avian vet in your contacts list.

Internet forums can be a wealth of (mis)information. Be very cautious with the advice provided as sometimes well meaning comments can lead to very ill (or worse) pet chickens.