Intestinal worms

There are three main species of worm that can cause problems in your flock:


These are large white worms found in the small intestines. In small numbers these are fairly harmless. However, once the numbers start to increase birds will start to scour, have anaemia, struggle to digest feed effectively, lose weight and cause the number of eggs and the egg quality to drop. In severe cases, these worms may cause an intestinal blockage.


These are small hair like worms that are found in the blind ended sacs known as caeca. They are mainly an issue as they are known to carry a protozoa known as Histomonas Meleagridis which can cause the disease 'blackhead'.


These are small, thin barely visible worms that inhabit the crop and intestines. They burrow into the walls and cause inflammation of the infected area. Severe burdens can lead to death.


This disease is usually a disease of younger birds as older birds develop immunity to it. It is not caused by a worm but by a protozoa known as coccidia.

Birds will appear hunched with ruffled feathers, be scouring, lose weight and in some cases become anaemic. Droppings may also contain red mucus.

Different species of Coccidia are species specific and even within those species will only affect certain areas of the gut. It damages the intestinal walls causing inflammation, cell damage and in some cases bleeding.

The most common types of Coccidia are:

  1. Acervulina – causes inflammation in the upper part of the small intestine.
  2. Maxima – causes inflammation throughout the small intestines.
  3. Tenella – causes bleeding into the caeca.

How is best to manage worms and coccidiosis in my birds?

In older birds, we recommend performing a worm egg count every two to three months to check worm egg levels. Usually if any Heterakis or Capillaria eggs are detected we recommend worming with a licensed product such as Flubenvet (flubendazole). Herbal products have limited use and there is little evidence that they can provide a benefit in clinical cases of worms.

In younger birds it is important to monitor for coccidiosis. We also recommend performing a coccidial oocyst count if birds are beginning to show symptoms. There are many different treatments available for coccidiosis. Discussion with your vet would be advised.

[caption id="attachment_1156" align="aligncenter" width="225"]Intestinal Worms From left to right : Tapeworm, Ascardia (large worm), Heterakis (small worm at top right)[/caption]

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Mites and Lice

There are many species of ectoparasite that can be found on poultry. Below are some of the more important species than can cause disease. They can be divided into two groups:

  • Permanent or stationary parasites – lice, scaly leg mite and northern fowl mite. The parasites mainly live on the bird: they cannot survive long in the environment.
  • Intermittent bloodsucking parasites – red mite. There are only a few individuals that remain on the bird. The majority live in the environment and only approach the bird to feed.

Red mite

These mites are the most common ectoparasite of poultry in the world and have a massive economic impact on the commercial chicken industry. They feed during the night and spend about 30-60 minutes on the host at any one time. Otherwise they can be found in dark places such as under perching and in cracks in the coop. Reportedly, red mites can survive without feeding for up to nine months. This can make them very difficult to eliminate from your flock and housing. Like many parasites, they can also be a carrier of many viral and bacterial diseases such as Newcastle disease and Salmonella. These mites are very small and can appear black or red. They have been known to bite humans and may cause an itchy rash or allergic reaction.

[caption id="attachment_1302" align="aligncenter" width="300"] Red mite under microscope.[/caption]

Symptoms in the bird.

  • Stress related behaviour (increased vocalisation, pecking, flightiness or aggression).
  • Decreased egg production.
  • Pale combs and wattles (anaemia).
  • Blood streaks or spots on eggs.


  • Visual inspection of the shed and chickens; Red mites like places such as perches, nest-boxes and cracks and crevices. They are very small and if they are present rubbing crack debris across the back of your hand will result in a red streak (the mites last meal; chicken blood).
  • The presence of abnormal flock behaviour.
  • Glue traps, straws taped to the bottom of perches or corrugated cardboard can be used to catch mites to check for their presence.


  • There are two areas to target for effective red mite control.
    • The coop – the most important area to target;
      • Remove all bedding and wash the coop out thoroughly.
      • Treat the coop with disinfectant products that have some action against red mite such as Poultry shield or Harmonix.
      • Cover the coop liberally, cracks and perching with diatomaceous earth powder.
      • In cases of wooden coops, due to the large number of hard to reach cracks and crevices it may be easier to dispose of the coop (burn it).
    • The bird;
      • Introduce diatomaceous earth dust baths, this product can be bought online, mixing this product with some standard soil may encourage the birds to use it.
      • Use products such as Exzolt (available from some poultry vets) – this will kill the mites once they feed on the birds.

Control and prevention

  • Red mite control is a war not a battle. You must target the red mite from several angles to keep it under control.
  • Introduce dust bathing boxes containing diatomaceous earth, kaolin clay or a sulphur-based product. Provision of dust boxes may be a simple and effective method of external parasite control for a backyard flock as well as good entertainment for birds.
  • Good premises hygiene – frequent cleaning and close observation to check if any red mite are present. If they are present, treatment as soon as possible is advised.


Northern fowl mite

Also known as the American louse because of its strong presence in North America in many domestic and wild birds. However, it is also found in Europe. Its appearance is almost identical to red mite but it lives its entire lifecycle on the bird and cannot survive for extended periods of time in the environment. The mites can be easily seen by parting the feathers around the vent region. The skin in that area may also be cracked with scabs. Young birds tend to be more susceptible.


  • Pale wattles and combs.
  • Death due to anaemia.
  • Mites are commonly first discovered around vent region or seen on eggs.


  • Visual inspection of the shed, birds and eggs.


  • Birds should be treated directly with a suitable mite powder, spot on or through the drinking water.

Control and prevention

  • Good hygiene – frequent cleaning and regular bird checks in order to spot the mite. If they are present, treatment as soon as possible is advised.
  • Restrict access to wild birds as much as possible. Drinker and feeders are common shared contact areas.
  • Introduce dust bathing boxes containing diatomaceous earth, kaolin clay or a sulphur-based product. Provision of dust boxes may be a simple and effective method of external parasite control for a backyard flock.


There are more than 40 different species of lice: the most common include the body louse, the shaft louse and the head louse. More than one species can be present on the bird at one time. The entire life cycle of a louse takes place on the host and transmission between birds occurs via direct contact with another infected bird.  Female lice can lay a significant number of eggs over a very short period, which can be seen on the base of feathers by naked eye. They mainly feed on skin fragments and feather debris. Lice infestation appears to be worse in the autumn and winter.


  • Reddened, irritated skin with small scabs.
  • A moth-eaten appearance to feathers.
  • Visible lice around the vent region.
  • Loss of feathers.


  • Lice can be easily seen with the naked eye: they are yellowish in colour.


  • Treatment option are variable, similar to above.

Control and prevention

  • Clean and disinfect the housing thoroughly.
  • Replace the litter completely, paying special attention to the nests.


Scaly Leg Mite

Otherwise known as ‘Knemidocoptes mutans’. This mite is microscopic and burrows between the leg scales of chickens.


  • Painful swollen legs.
  • Raised leg scales (sometimes can be very discreet).
  • Crusted legs.


  • Visual inspection of the leg is often enough.


  • Some spot on treatments on the back of the neck have shown effectiveness. Usually Ivermectin 1%.
  • Submerging the leg in a methylated spirit and then smothering the mites by applying Vaseline for a few days may be enough in the early stages of scaly leg. Continue the treatment until all symptoms have gone.

Control and Prevention

  • Stay vigilant for the early signs of the parasite (raised leg scales).
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Otherwise known as 'pododermatitis'. This condition occurs when the environment that the birds are in is suboptimal; Wet bedding, stony environments (that may cause abrasions) or wire. This may mean the footpad is under too much pressure and sores develop.

This is a very painful condition and will be visible initially as lameness in your hens. It comes in varying severity and may require surgical intervention and antibiotics in severe or long-term cases.

Treatment and Prevention

If your bird is struggling with bumblefoot, first clean the wound with an appropriate antiseptic wash such as hibiscrub or salt water. Bandaging with a soft foam ring covered by cotton wool and vet wrap will help it to heal more quickly as it will take the pressure off the foot pad (see the diagram below). The foot should be flat so that weight can distribute evenly between all four toes.

This should be changed every couple of days and not allowed to become wet.

[caption id="attachment_1300" align="aligncenter" width="300"] 1-2: Clean and disinfect wound. Measure and apply foam ring, all toes must be supported. 2-3: Apply cotton wool/ softban in figure 8 pattern. Ensure bandage pressure is not constrictive. 3-4: Apply Vetwrap/ veterinary adhesive layer to secure soft layer. Again ensure excessive pressure is not applied.[/caption]

It is also important to address the causes of bumblefoot:

  • Softer bedding/restrict access to rough areas.
  • Remove them from the wire or provide somewhere for your birds to stand to get away from it.
  • Frequent wet bedding removal.
  • Allow the birds to exercise more freely.
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The abnormal Egg

What is safe to eat?

The egg can tell us a lot about the health and nutritional status of a hen. In the backyard flock there are often questions over what is safe to eat or not.

Diseases such as infectious bronchitis, aMPv and mycoplasma  (which all cause snicking, head shaking, nasal discharge), Newcastle disease (see notifiable diseases) and egg drop syndrome (a decrease in egg production caused by adenovirus) may also cause some of the egg abnormalities below.

If any bird begins to produce an abnormal egg on multiple occasions, seek the advice of your vet. Otherwise you may use this guide:

Egg shell abnormality Causes Safe to eat?
No shell/soft shell Young birds coming into lay. Sulphonamides (antimicrobial treatment, shouldn’t be used in layers). No – risk of bacterial contamination.
Misshapen eggs Young birds coming into lay. Older birds (due to reduced muscle tone in oviduct). Early calcification causing uterine damage. Adrenaline release due to stressful events such as moving and handling. Yes
Corrugated eggs Legume seeds such as peas. Yes
Flat sided eggs Release of two eggs into the reproductive tract at one time. Abnormal uterine pressure during calcification process. Yes
Thin, soft eggs Imbalanced ration: inadequate calcium, phosphorus, manganese and vitamin D3. Inadequate feed intake. Excessive temperature. Night disturbance disrupting the shell formation. Sulphonamides (antimicrobial treatment, shouldn’t be used in layers). Old birds.   Caution
Rough surface Sulphonamides (antimicrobial treatment, shouldn’t be used in layers). Excessive calcium. Young birds coming into lay. Aging birds due to reduced muscle tone in oviduct. Adrenaline release due to stress. Yes
Mottled egg surface Humidity extremes. Marks from environment (e.g. red spots may be red mite) Yes
Yellow shells High levels of tetracycline antimicrobials. No
Cracked eggs Too high stocking density. Inadequate cage design, poor collection method. Reduced shell thickness. Avoid as risk of bacterial contamination.
Pale eggs Free range birds (sun bleaching). Sulphonamides (antimicrobial treatment, shouldn’t be used in layers). Nicarbazin (coccidiostat not routinely used) given in feed. Piperazine (wormer not routinely used). Yes – providing no history of drugs as mentioned.
Egg contents abnormality Cause Safe to eat?
Loose air cell Rough handling. Yes
Blood spots Inadequate environmental temperature. Birds have continuous light. Nutritional deficiencies: vitamin K, vitamin A. Stress. Mycotoxins (moulds/fungi – contaminated feed, feed bins, bedding). Vent pecking by other birds. Red mite infestation. Aging birds. No
Abnormal yolk colour Diet: access to pigmented plants, cottonseed and kapok seed meal in feed, oxidative breakdown of natural or synthetic carotenoids due to immunological challenge or inadequate vitamins in diet. Any underlying infection causing immune suppression will result in ingested carotenoids being broken down (oxidation) and used as antioxidants, instead of contributing to yolk colour. Birds require a healthy gut in order to absorb carotenoids from the diet. Bacterial contamination. Yes, as long as not green.
Reduced yolk colour (with adequate carotenoid in feed) Inadequate feed consumption. Mycotoxins. Oxidative breakdown of carotenoids due to immunological challenge and/ or inadequate vitamin uptake. Intestinal parasites. Yes – as long as birds appear healthy.
Mottled yolk Mild level of mottling is normal. Abnormal mottling may be a result of: Excessive dietary pigment, excessive chilling of eggs or partial freezing when laid in free range environment, high storage temperature. Yes, if at a mild level.
Cheesy appearance of yolk Chilling of eggs in free range systems, cotton seed meal, kapok seed meal. Avoid
Yolk taint Some birds genetically lack the enzyme for breaking down trimethylamine (TMA) in fishmeal, resulting in a fishy taint in the yolk. Excess dietary choline as TMA is released by bacterial fermentation of choline in the gut. Using unsuitable detergents to clean the eggs and storing them near strong odours during cooling may also result in taint. No
Flat yolk Nicarbazin (coccidiostat). High storage temperature. Excessive storage times. Inappropriate storage with eggs stored blunt end down. Watery white. No
Watery white   Warm and prolonged storage. Genetic predisposition.   Yes if fresh. No if stored for too long.
Pink white Cottonseed oil, kapok seed meal. Excess iron in water or feed. Bacterial contamination No
Abnormal chalaza Prominent chalaza is associated with watery whites. Ruptured chalaza may result from infectious bronchitis. Yes
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