Common Health Problems of Domestic Poultry

The most important thing when it comes to keeping chickens healthy is good husbandry.

  • suitable housing that is kept clean
  • a good diet
  • a happy environment
  • preventative worming.

The following issues are those most commonly seen, however if you have any concern at all you should seek veterinary attention. There are of course many issues that are not covered in this blog post.


One problem that is not a medical one but is worth noting is broodiness. A hen that goes broody will spend most of her time in the nest box sitting on the eggs, usually becoming defensive of the nest and staying put even if the eggs are removed.

As the hen will rarely leave the nest she will not take in sufficient food and water and gradually loose condition. Hence, if she is not being allowed to sit on eggs and hatch them then we need to stop her being broody or keep her healthy while she stops herself.

If the hen is allowed to sort herself out then she will need removing from the nest several times a day and placing by the food to encourage eating and drinking.

If the hen is to be forced out of broodiness then typically the aim is to keep the hen somewhere for a few days where she would not want to sit eggs or raise chicks. Many keepers use a small enclosure such as a cat box, providing food and water and keeping the box somewhere light (such as within the chicken run) so she will not want to sit on eggs.

Some hens, usually pure breeds, will go broody frequently throughout the Spring and Summer. Hybrid hens are much more likely to continue laying and leave the nest alone the rest of the time.


Again not a medical problem but one that often upsets new chicken keepers is their hens’ first full moult. This will usually be in their second Summer/Autumn (so after a full year of laying).

Some birds moult gradually, losing a few feathers here and there at any one time, others seem to end up almost bald as they drop lots of old feathers at once. This is a normal process and not anything to worry about – you should be able to see the tips of the new feathers coming in through the skin.

Some birds find this uncomfortable and may get grumpy about being handled.

It is worth monitoring them at this time in case it is something else, there should be no redness or irritation to the skin during a healthy moult. It is also worth noting that hens will stop laying during a moult, but many hybrids will resume a normal laying pattern afterwards.

Sometimes moulting can occur out of season, brought on by illness, extreme heat or other stresses. Moulting will also take longer to clear if the diet does not contain sufficient protein.


Feather pecking should not be mistaken for moulting. Feather pecking is usually a symptom of imbalance in the social order of the hens or of bullying. Feathers may be broken as well as pulled out and the skin may be damaged.

How the situation is resolved will really depend upon the cause of the problem. Some keepers remove a bully hen for a few days so that when she is put back (into the coop, at night) she is lower down in the order. Usually it is best to watch the hens carefully to see who is doing what.

If you spend a lot of time with your hens you will generally notice a problem before it gets too bad. If a hen has been injured by the others then she should have veterinary attention. If there is no obvious damage by other hens then there may be a parasite problem so attention should also be sought.

It is worth noting that a cockerel will often damage the feathers on hens’ backs, particularly if he is larger, so claw/spur trimming and possibly removal of the cockerel may be beneficial.



This is not an abnormality if a chicken is at the beginning or end of lay, as their egg producing systems often make the odd error at this time! It is also not unusual for this to happen if the chickens have had a big fright such as a predator attack among the flock or some disturbance to their living arrangements (e.g. moving house).

We would recommend never keeping ducks and chickens together

If the production of thin/non-shelled eggs persists for more than a few days without obvious cause then it may be worth having the health of the birds checked. There is a (rare) virus that can cause problems with egg laying which can be carried by ducks, which is why we would recommend never keeping ducks and chickens together or keeping chickens in an area where they may come into contact with wild ducks.


This may result from a bird eating lots of long grass, or may occur in birds where there is a loss of muscle tone (usually older hens).

Severe crop impaction may be an emergency case

In some cases it may resolve if the bird is offered water only for 48 hours, however by the time it is noticed it is usually far too impacted for this to work and in some cases may require surgery.

Severe crop impaction may be an emergency case – if left then the crop can rupture.

Crop impaction can be prevented by keeping birds off long, fibrous grass and ensuring they get plenty of grit.


There are many causes of diarrhoea, including infectious agents such as bacteria and coccidia. In these cases remember that affected birds will be infectious to other hens.

Inappropriate food treats or incorrect diet can also lead to diarrhoea. Dirty feeders or water supplies and a generally unclean environment will make birds more likely to be affected, particularly by bacterial diarrhoea.

Affected birds may look ruffled or hunched up, their bottom may be dirty or the feathers around the vent, droppings will be loose (causing wet bedding) and sometimes bloody and the birds lose weight.

It is worth noting that while coccidiosis can cause diarrhoea it can also cause other health problems such as anaemia (you will see a pale comb and wattles) and sudden death.

Cleaning and disinfecting the environment is the most important part in preventing diarrhoea.

Keep feed and water supplies clean, change bedding frequently and disinfect all housing on a regular basis. Treats should be appropriate for chickens and fed in small quantities.

It is wise to seek veterinary attention for any bird that appears unwell and to keep new birds separate for several weeks before introducing them to your flock.


There are many causes of respiratory disease in chickens so diagnosis is often tricky. The most important thing is to treat any problem as early as possible and keep stress levels low in affected birds.

Causes can include Infectious Bronchitis, mycoplasma and several other bacteria and viruses, often in combination. Most of these are carried for life and so can flare up when a bird is stressed.

Often egg production will be affected while a bird is ill but in some cases loss or deformity of eggs will be permanent.

Respiratory infections can appear as

  • Runny eyes and nose
  • Sneezing, difficulty breathing
  • Change in egg laying.
  • Often the affected birds will look a bit ruffled and be quiet, tending to adopt a hunched posture.

Sometimes only one symptom will appear or they may have many.


Worms are very common in chickens, some cause disease and some don’t but most will weaken the bird and their immune system making them more prone to disease and problems with egg production.

It is very important to worm chickens that come into contact with wild birds (i.e. chickens that have access to the garden) and also birds that are kept on the same ground all year as they will become re-infested from the contaminated soil.

Many worms won’t be visible as they stay within the bird’s system – only a few will appear in the faeces. Some worms may be associated with diarrhoea, but the most obvious worm to cause disease symptoms is gapeworm; as the name suggests it causes the chickens to open their beak wide in a gaping breath as it infects the airways. Some infections will not cause gaping so preventative treatment is still worthwhile.

We would suggest using Flubenvet at least twice a year, more often in higher-risk flocks. This is a powder that you mix with the birds’ feed, and it treats all the common worms of chickens. It is a licensed product for chickens and has no withdrawal period for eggs – the eggs the hen produces are unaffected by the wormer so can be used as normal.

Panacur is an alternative wormer but it does not treat gape worm.


Red mite is probably the most common parasite of chickens and one that needs constant attention all year around. The mites only appear red when they have fed – unfed mites appear dusty grey to brown. The mites are clearly visible to the naked eye and will be found in nooks and crannies in the coop and under perches.

A bad infestation left untreated will eventually lead to the death of the hens.

Mites hide in the dark during the daytime and feed on the perching hens at night. Mite populations can quickly reach huge numbers causing anaemia, weight loss and reduction in egg production. Mites may well show up as red dots on the eggs – these are mites that have been squashed by the hen or by you picking up the egg!

  • The most important step is using suitable housing in the first place, with a minimum of cracks and crevices.
  • Bedding needs to be cleaned out frequently and in bad infestations it may be necessary to burn bedding full of mites.
  • Do not compost waste from affected housing as the mites can survive a very long time in the environment.
  • It may be necessary to spray housing with insectides such as poultry housing spray or household flea spray.
  • As the mites live in the house not on the birds it is mainly the housing that needs treatment.
  • A bad infestation left untreated will eventually lead to the death of the hens.


Scaly leg is caused by mites and requires treatment to kill the mites. If left, then the legs will get continuously worse and will be uncomfortable for the chickens.

The scales will not be replaced until a full moult takes place so can take up to a year to return to normal. There are various products available to treat this condition.

Keeping Your Hens Healthy