Worming Chickens and other Poultry

Worming chickens and other poultry is a straight forward process, but it does help to know a little bit about the worms that are likely to infect your birds and their life-cycle so you can control and manage their numbers, minimising the worm burden on your flock.

Dont-be-chickenThis article describes the most common worms that infect chickens, how you can reduce the worm burden, when you should consider worming, what products you can use and other questions that are often asked. (Image right courtesy of Elanco).

Whilst most of this information is common to all poultry, I tend to talk about chickens for simplicity. A separate article has been written here specifically for Worming Ducks.

Worms and chickens

Ectoparasites are found on the outside of your chickens - an example being lice or mites such as Northern Fowl mite. Endoparasites on the other hand are found on the inside of your birds body and are referred to as Helminths in the veterinary world which is a term used to cover a wide range of internal parasites or 'worms' as we commonly call them.

The most important group of worms that concern us are called Nematodes. These worms inhabit various parts of the digestive tract and are listed below. All of the worms listed are part of this group, with the exception of Tapeworms which are part of a group called Cestodes.

The links take you to more information about a particular kind of worm. Perhaps you know which worms are infecting your chickens and want to learn more about them.

The following types of worms can be found in poultry:

The following types of worms can be found in poultry:
  • Hair worm - Found in the crop, oesophagus, proventriculus and intestine. Also called Capillaria.
  • Roundworm - Found in the birds digestive system.
  • Gizzard worm - Found in the gizzard, mainly in geese. A common problem for goslings.
  • Tapeworm - Fairly uncommon, found in the intestine.
  • Gapeworm - Found in the trachea and lungs.
  • Caecal worm - Cause little damage but transmit blackhead to Turkeys.

Worming chickens is important because most infections of these worms can cause damage and eventually death. So let's look at the lifecycle of these worms to understand them a bit more.

The lifecycle of poultry worms

There are two ways worms are commonly picked up by chickens (excuse my terrible drawing, I never was good at art).


1Direct Life-cycle: Worm eggs are expelled from an infected bird in droppings, by the thousands. These eggs sit on the ground surviving for up to a year before being picked up by birds foraging when they are feeding. Large Roundworm, Gizzard worm (that affects geese), Hair worms and Caecal worms follow a direct life-cycle. Hair worms can also follow an indirect lifecycle.

2Indirect Life-cycle: Worm eggs are expelled from an infected bird by the thousand. This can be in droppings, or in the case of gapeworm that are found in the respiratory system, coughed up. Worm eggs are not infective at this stage. Intermediate hosts, (such as earthworms, slugs, snails and centipedes) will eat these eggs and (you've guessed it) your chickens will eat these intermediate hosts and the worm eggs they have ingested and your birds become infected. The larvae hatch inside your chickens and the cycle repeats. Hair worms, Gapeworms and Tapeworms follow an indirect life-cycle although hair worms can also follow a direct lifecycle as well.

Health problems caused by worms

Many health problems that your occur can be related to an infestation of worms of some sort, so it is important to not only worm your birds regularly but manage houses and runs correctly in between worming treatments (more on this later though).

Signs and symptoms of worms

The signs and symptoms of chickens with worms are listed under each particular type of worm on the individual pages via the links above, but there are many different symptoms and the first question a vet will usually ask when examining a sick bird is "When was he / she last wormed...?" so it is worth ensuring you have a worming routine just to make sure you don't have problems.

Gaping-chicken-largeThe most common symptoms are loss of weight / poor weight gain, increased feed consumption, pale yolk colour, diarrhoea and in severe cases, anaemia (pale comb and wattles) mortality. In the case of gapeworm, chickens will gasp for breath or 'gape' stretching their neck.

Photo Right: Gaping (gasping for breath) as gapeworms block the airway. Photo courtesy of Elanco.

Diagnosing worms

Getting a 'worm egg count' is the way a vet would diagnose a case of worms. You don't have to go to your vet to get this done any more, it can be done by submitting some fresh droppings (from as many of your birds as possible in your flock, try to include Caecal droppings too - the yellow-brown foamy coloured dropping that is expelled every 24 hours or so) to a poultry veterinary laboratory service such as that offered by Chickenvet. Chicken-vet-advert-2They post a kit to you with everything you need to collect and send off the sample and then the results are sent to you after they have examined the samples under the microscope.

Many poultry keepers though are on a budget, so more often than not, they will worm their chickens as a precaution if they suspect worms, without going to the trouble and cost of a worm count.

Damage caused by worms

The damage caused by worms will be in the part of the digestive tract (or respiratory tract in the case of gapeworm) in which the worms live. Typically, in the gut, worms cause anaemia and haemorrhaging and in sufficient numbers can impact (block) the gut. They not only damage the gut but also take nutrients and their waste releases toxins.

The photograph below (courtesy of Elanco) shows an impacted gut, full of roundworms. As you can see, it isn't very nice.


The next photo shows gapeworms in the trachea (the wind-pipe) of the respiratory system The gapeworm are red in colour and Y-shaped.Gapeworms-chicken

Looking out for worms

One of the things you can do in keeping an eye out for worms is to inspect droppings regularly, although unless there are large numbers of worms, there aren't always worms present in droppings but you may like to do this to see what comes out when worming your chickens.

A sheet of newspaper on the floor under the perches (weighted down on the edges so it doesn't move when birds flap their wings) can be used to collect droppings. A jam jar part filled with water can be used to separate droppings by shaking and then to inspect the contents by holding it up to the light.

Here is a brief description of the most common worms:

  • Hair worms – as the name suggests are really thin. They are up to 1.5cm long but hard to see with the naked eye. Normally, in a post-mortem, intestinal scrapings will be mixed with water in a petri-dish and the thin white threads can then be seen against a black background.
  • Roundworms – are the easiest to spot although there are often only a few adult worms in the small intestine, up to 8cm long, that look like spaghetti (the photo below was taken on day 2 of administering Flubenvet to a group of hens).

Chicken Worms 15156-2

  • Gizzard worms that affect geese can be found after death. Goslings raised on pasture with older geese are particularly vulnerable. They will stop growing and slowly waste away. Take the gizzard and swill it around in a jam jar full of water. Hold it up to the light and you will usually see very fine gizzard worms around 2cm long coming away from the mucous lining.
  • Tapeworm – are very small reaching only 3-4mm long and are hard to spot due to their size. Tape worm segments that are shed and deposited in droppings are much easier to spot. The photo below (courtesy of chickenvet) shows a dropping with tapeworm segments clearly visible.


  • Gapeworm – are red in colour, up to 2cm long and Y-shaped. This is the male and female joined together (how romantic!)
  • Caecal worms - are grey to white in colour up to 1.5cm long and are S-shaped.

Worm eggs are too small to be visible with the naked eye and have to be identified under a microscope.

Good husbandry – preventing worms

Here are some tips to making life more difficult for worms.

  • Worm eggs thrive in wet, warm, muddy areas. Remove muddy areas such as those found by pop-holes by creating hard standing or free draining gravel.
  • Worm eggs cannot develop when it is very dry, when the temperature is below 10˚C or above 35˚C. Worm chickens as the temperature rises in spring.
  • Worm eggs are destryed by Ultra-violet Light (UV) from the sun. Keep grass short and rotate pasture in the summer if you can to help prevent a build up of worm eggs.
  • Keep litter in poultry houses fresh and always ensure it is dry.

Prevention is always easier than cure so follow good husbandry techniques and combined with regular worming (according to the manufacturer's instructions), you shouldn't see any problems.

Products that can be given regularly to help reduce worms

Diatom (in feed), Apple Cider Vinegar (ACV) and fresh crushed Garlic (both usually given in water). These are believed to make the gut an unpleasant place for worms. Before wormers were invented, garlic cloves crushed into water was often the remedy given in the old poultry books.

Products to worm poultry


There are a number of different wormers available in the UK. Some are not licenced for poultry but vets can prescribe these under what is known as their 'clinical judgement' if there isn't a licensed alternative available. They will advise you on an egg withdrawal period for unlicensed products which by law has to be a minimum of 7 days.

Flubenvet - in the UK, this is currently the only licensed in feed wormer for Chickens, Turkeys, Geese and Pheasants that can be mixed with your poultry feed. The 60g pack is available to buy online, the Amazon Marketplace usually has a number of sellers that are competing for the best price.

Where to Buy Flubenvet.

The 60g packs of Flubenvet 1% contain enough to treat around 20 large fowl. They come with a handy plastic scoop for measuring out the required amount so you don't need accurate electronic scales as you would with the larger 240g Gamekeeper packs that are only available from a few suppliers.


Specialist suppliers of pet medication sell Flubenvet. Premixed Flubenvet with Layers Pellets are also available on Amazon (see advert right) which is an easy way to use Flubenvet.

Solubenol - A water soluble wormer used for the treatment of worm infestations caused by large roundworm, caecal worm and capillaria worms. This is often used commercially so will sometimes be in stock at your vets.

Ivermectin - An anti-parasite medication, effective against most worms (not tapeworm), mites and some lice including scaly leg mite and northern fowl mite. Ivermectin pour-on / drops is applied to the skin. Unlicensed for use in poultry so should only be purchased and used at the advice of your vet.

Panacur - A wormer that is commonly used for cats and dogs but is a broad spectrum wormer that some vets may prescribe for poultry. Unlicensed for use in poultry and only available on prescription from your vet.

Herbal products

Herbal products -may- only reduce worm numbers and may not be as effective as using a chemical wormer. The approach I have taken with my own birds is to use herbal / organic products on a monthly basis but still use chemical wormers (Flubenvet) every 6 months routinely and would use Flubenvet if my birds had a suspected worm problem.

Verm-X (click to see my review) is the market leader and is suitable for use in Organic production.

When to repeat treatment

If you are worming as part of a prevention routine, most poultry keepers worm at least every 6 months with Flubenvet, usually in the spring before the breeding season, as the temperature rises and worm eggs become infective and again at the end of summer as egg numbers decline.

However, if you know your chickens have worms or you see worms expelled in droppings after treating your birds with Flubenvet, then do remember that this kills the worms they are carrying but does nothing about the worm eggs that are on the floor of the run and in the intermediate hosts such as slugs, snails and earthworms. You do need an ongoing treatment plan to kill the worms that develop over the coming weeks as a result of the eggs that get picked up.

The lifecycle of the worm varies between 2 and 8 weeks (see the information below) and is called the "prepatent period" of the worm, so you will need to repeat treatment before these eggs develop into egg laying adult worms producing thousands more eggs.

Note that during the prepatent phase of infection, poultry can harbour lots of immature worms that are not laying eggs, so no eggs will be present in the droppings.

Treatment should be repeated within this period, 3 weeks after the end of the last treatment (2 weeks for geese) is a good compromise if you don't know the type of worms that are infecting your birds.

Prepatent period of common poultry worms:
  • Hair worms – 20 to 60 days depending on the type of Hair worm.
  • Round Worms – 35 to 56 days faster in young growing birds.
  • Gizzard worms and tapeworms -14 to 22 days.
  • Gapeworm – 18 to 20 days
  • Caecal worms – 24 to 30 days.

It very much depends on how your birds are kept and managed as to how many worms they will get. Infection may persist for many years, on well used ground but with good husbandary and regular worming, you shouldn't have too many problems.