This article describes common worms that infect chickens, how you can reduce the worm burden, what products you can use and how often. Most of this information is common to all poultry, but I talk mostly about chickens for simplicity. A separate article has been written here specifically on Worming Ducks.
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.
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. (Image courtesy of Elanco).
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:
- 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 life-cycle of these worms to understand them a bit more.
The life-cycle of poultry worms
There are two ways worms are commonly picked up by chickens (excuse my terrible drawing, I never was good at art, if someone is interested in re-drawing this for me?).
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 life-cycle.
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 life-cycle 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.
The 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.
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.
The worm egg count kit contains everything you need to collect and send off the sample to the lab, then the results are sent to you after they have examined the samples under the microscope. Expect to pay £12-18 for a kit compared to £40 upwards at a vets.
Many poultry keepers are using these kits now as the price of Flubenvet has gone up dramatically and has become harder and harder to find. Add to this the fact that routine worming causes drug resistance, it’s always better not to treat your birds unless you really have to.
You can buy worm kits here.
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 right (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 gapeworms are red in colour and Y-shaped.
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 to the right was taken on day 2 of administering Flubenvet, a wormer (in the U.K.) to a group of hens.
- 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. Weight loss is usually the first sign which you will notice if you handle your goslings regularly.
- 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 right (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!). You may see chickens gasping for breath (gaping) as shown earlier in this article. They are much more common in pheasants and your chickens are more likely to pick up gapeworm if they free range on ground that has pheasants visiting.
- 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 destroyed 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 used 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.
Sanitising powders such as Net Tex Ground Sanitising Powder used on the floor of the coop and run absorbs moisture and oxygen from worm larvae and faeces where parasitic worm eggs would develop and mature.
Products to worm poultry
There are a number of different wormers available in the UK. Some are not licensed 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.
If you want to buy Flubenvet now, you can buy it here in pre-mixed in layers pellets. If you want to look at the different size packs and ways to buy it with their pros and cons then the options are presented in the tabs below.
Which Flubenvet is right for you?
As a general rule of thumb 20Kg feed is enough for 20 large fowl chickens for 1 week but different breeds consume different amounts and consumption varies according to the time of year (in winter they eat more to keep warm).
Flubenvet Pre-Mixed with Layers Pellets
Flubenvet can also be purchased pre-mixed with layers pellets and is the best option for most back-garden chicken keepers.
These are produced by companies such as Marriages or Heygates and can be bought online here.
The sell by date is usually at least 6 months.
Expect to pay £11-£12 for 20Kg, £6-£7 for 5Kg plus postage (which can be as much again) but remember to take into consideration the cost of a normal bag of feed (around £9-£10 for 20Kg) so this is usually cost-effective and there is no fiddly mixing required.
Flubenvet 1% 60g Pack
This pack contains enough to medicate 20Kg feed / enough to treat 20 large fowl.
If you have a few hens, it comes with a handy plastic scoop (approx. 6g) for measuring out the amount so you don’t need accurate electronic scales as you would with the larger 240g Gamekeeper packs.
The sell by date is usually at least 12 months.
Expect to pay around £25 plus postage best found through an online search.
More Information about this product can be found here on our Flubenvet 1% 60g page.
Flubenvet 2.5% 240g Pack
This is called the ‘Gamekeeper pack’ and contains enough to medicate 100Kg of feed / enough to treat 100 large fowl.
Useful if you have a large number of hens to treat (but I would still consider Flubenvet pre-mixed with layers pellets). You will need accurate electronic scales to measure down to 0.1 grams. The sell by date is usually at least 12 months.
Expect to pay around £65 plus postage. It is available from specialist suppliers such as Bowden and Knights or The SPR Centre.
More Information about this product can be found here on our Flubenvet 2.5% 240g page.
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 but beware, it needs careful mixing and must be used in quite a short time by your hens.
Ivermectin – An anti-parasite medication, effective against most worms, 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 used at the advice of your vet but is still a very popular treatment because of its dual use killing lice / mites as well.
The number of worm species that are killed by Ivermectin is more limited. Victoria Roberts book ‘Diseases in Free Range Poultry’ suggests that tapeworm and fluke are excluded.
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 – 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 I would use Flubenvet if my birds had a suspected worm problem.
Verm-X (click to see my review) is the market leader in herbal ‘intestinal hygiene’ products and is suitable for use in Organic production.
Verm–X is not a licensed medicine which is why it cannot be called a ‘wormer’ or ‘anthelmintic’ and in the same vain the company producing Verm-X are not allowed to publicise client testimonials, test results or describe the properties of each herb they use so it’s hard for them to show its efficacy. You can buy Verm-X here.
When to repeat treatment
If you are worming as part of a prevention routine, most poultry keepers worm at least every 3-6 months with Flubenvet. As a minimum, 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 life-cycle 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 husbandry and regular worming, you shouldn’t have too many problems.
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