Short answer: Inclusion body hepatitis (IBH) is a viral liver disease caused by fowl adenoviruses. It usually strikes broilers between three and six weeks old, often with a sudden rise in deaths and a pale, enlarged liver at post-mortem. The virus can travel through eggs, litter and equipment, so prevention depends on clean houses, low stress, good feed and a vet's check on the parent flock.
Key takeaways
- IBH often shows up at three to six weeks, when the birds are growing fast and the maternal protection they came with is fading.
- The most useful clue is the liver at post-mortem, which is usually enlarged and pale, and this needs a vet to confirm.
- Stress from another infection or from mouldy feed is often what lets the virus take hold in a flock.
- Adenovirus is not on the list of vaccines we give at the hatchery, so ask your supplier what the parent flock received.
- When birds start dying, take fresh carcasses to the vet at once and keep the house quiet while you wait for the result.
A flock that looked fine on Thursday
Inclusion body hepatitis kills young broilers quickly, and it often gives no warning the day before. The birds are eating, the litter is dry and the house is quiet. Two days later there are dead birds at the feeder line, some with their heads tucked in and others flattened out on the floor. Farmers describe that pattern to us, and it is the reason this disease is feared in the grower phase.
It is a viral disease caused by fowl adenoviruses. The name refers to the inclusion bodies that the virus leaves inside liver cells, which a vet can see under the microscope. The disease is not always the same from flock to flock. Some outbreaks are short and sharp, others drag on and cost birds across two or three weeks.
What the adenovirus does inside the bird
Adenoviruses are a large family of viruses, and several of them infect chickens. The ones linked to IBH are fowl adenoviruses, and they can infect the liver cells directly. Once inside, the virus multiplies, the cell swells and changes shape, and a dark mark appears inside the nucleus. That mark is the inclusion body. When enough liver cells are damaged, the liver stops doing its work of clearing toxins and making the proteins the body needs to fight infection.
The bird does not die of the liver alone. A damaged liver leaves the immune system and the blood chemistry out of balance, and the bird becomes an easy target for other bacteria. That is why IBH often appears alongside other problems, and why a vet looks at the whole bird and the whole house, not only the dead birds on the floor.
Why the third to sixth week is the risky stretch
Day-old chicks come with antibodies from the hen, which protect them for the first days or weeks. Those antibodies fade, and the chick has to build its own defence. At the same time a broiler is putting on weight faster than its liver and immune system can easily keep up with. In a flock that has seen no adenovirus before, the birds in their third to sixth week are the most exposed.
The risk is not only about age. A house that has been crowded, a sudden heat spell that sends the birds to the drinkers all at once, or a late vaccine given in a stressed flock can tip the balance. Farmers who keep their birds calm and their feed clean tend to see the risk stay low, even when the virus is in the area.
The signs you can see before the birds die
IBH is not always easy to spot early, because the first birds to fall are sometimes the strongest feeders. Check the flock twice a day and watch for these changes.
- Birds that sit apart from the flock with ruffled feathers and their eyes half closed.
- Huddling in the corners, with birds piling up even when the house is warm enough.
- A pale or dull comb and wattles, which can look washed out compared with healthy birds.
- A sudden drop in feed and water intake, visible as a lot of feed left in the trough.
- Watery or greenish droppings in some birds, and a dirty vent in birds that are standing still.
- Deaths that come in a cluster over one or two days, rather than one or two a week.
If you see more than a couple of these signs in one part of the house, stop assuming it is the weather and call your vet that day.
What the liver tells you at post-mortem
The most useful evidence comes from a dead bird that has been opened by someone who knows what to look for. In IBH the liver is usually enlarged and pale or yellow, sometimes with small haemorrhages on its surface. The kidneys can look swollen and pale, and the spleen may be enlarged. Under the microscope the vet looks for the inclusion bodies in liver cells, which confirms the diagnosis.
Several other problems can make a liver look bad, and the table below sets out how a vet tells them apart at a glance. Treat it as a guide for the conversation with your vet, not as a diagnosis you can make yourself.
| What you see | Typical in IBH | Typical in mouldy feed toxicity | Typical in fluid around the heart |
|---|---|---|---|
| Liver | Enlarged, pale or yellow, with small bleeds | Pale, enlarged and sometimes firm | Often pale, with the heart sac as the main change |
| Heart sac | Usually clear | Usually clear | Full of clear or straw-coloured fluid |
| Kidneys | Can look swollen and pale | Can look pale | Often normal |
| Age of birds | Usually three to six weeks | Any age, often after mouldy feed for days | Usually three to five weeks |
| Feed clue | Often none | Mould or a musty smell in the feed | Often none |
A clean, pale liver in several birds at the same age is the signal to call the vet quickly, whatever the cause turns out to be.
A related syndrome with fluid around the heart
You may hear the term hepatitis-hydropericardium syndrome, or HHS, mentioned alongside IBH. It is caused by a closely related adenovirus and it hits broilers at a similar age. The difference shows at the post-mortem, where the heart sac is full of clear or straw-coloured fluid. Birds can die suddenly with very little warning, and a flock can lose a noticeable share of its birds in a short space of time.
Because the two look alike in a living bird, do not decide which one you have from the signs. Let your vet open a few birds and send samples for testing. The treatment and the prevention plan both depend on getting the diagnosis right, and a farmer who guesses wrong may spend money on the wrong measures.
How the virus travels through a farm
Fowl adenoviruses can move in several ways, and each one needs a different fix. The most important route is through the egg. A hen that carries the virus can pass it into her eggs, so a chick can start life already infected. The second route is horizontal, meaning from bird to bird. The virus sheds in droppings, and it stays in litter, dust and wet corners where it waits for the next bird to peck or breathe it in.
Equipment, boots, crates and people carry virus from house to house. A farmer who walks through a dirty pen and then into a clean one is a route, and so is a crate that went back to a neighbour's yard without cleaning. Water that stands in a trough or a drinker can also keep the virus moving between birds. The clean-house routine we describe for other diseases works here too, and our all-in-all-out guide explains why it matters most at the end of a batch. Our biosecurity guide covers the footbath and visitor routine in more detail.
The stress that lets the virus take hold
In many outbreaks the adenovirus is not the only problem in the house. A flock with another virus in its gut or its immune organs has less room to fight, and adenovirus finds the weakness. Mouldy feed is a common partner, because mycotoxins damage the liver and the gut at the same time. Ammonia from wet litter, crowding and sudden temperature swings add to the load.
Immune suppression from another virus is the classic set-up. The Gumboro guide covers how that virus damages the immune organ, and a flock hit by it can be far more open to an adenovirus infection. A vet may test for both when the picture is unclear, because the treatment for one does not fix the other.
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What the parent flock should have had, and why you should ask
The most effective defence against IBH in the chick is the protection the hen passes on. Breeder flocks are often vaccinated against adenovirus so that their chicks carry antibodies in the first weeks of life. Whether that vaccination was done depends on the parent flock and the supplier, so it is a fair question for any chick buyer to ask.
Our hatchery programme covers Marek's disease, Newcastle disease, Gumboro (IBD), infectious bronchitis and coccidiosis. Adenovirus is not on that list. That is not a gap we hide. It is simply why we tell buyers to ask about the parent flock's vaccination and to plan house hygiene and stress control on their own side. Your vet can advise on the timing for your flock. Our poultry vaccination schedule has the typical timings for the vaccines we do give.
Mould in the feed during the rainy season
In Ghana's rainy months, feed in a sack can turn mouldy within days if the store lets in damp air. Maize and groundnut cake are the common culprits, and they can carry aflatoxins that damage the liver. A flock on mouldy feed can show a pale, enlarged liver and sudden deaths that look very much like IBH, so the feed is one of the first things to check.
Store sacks off the floor and away from the wall, keep the room dry, and use the oldest sack first. Smell the feed, look for clumps and blue-green patches, and throw out anything that looks damp. Our broiler feeding schedule guide sets out the feed stages, and a clean feed store is part of the same plan.
What to do the day the first bird dies
The first death is the most important moment, because the samples you take now decide whether the vet can make a diagnosis. Do not wait for the deaths to add up. Work through the steps below in order and keep a written record of each one.
- Remove the dead birds from the house with clean gloves, and place them in a sealed bag.
- Call your vet the same day and tell them the age of the flock, the number of deaths and the signs you saw.
- Take two or three freshly dead birds to the vet, not birds that have lain for a day in the heat.
- Check the feed for mould and the water for any build-up or contamination in the drinkers.
- Keep visitors out and clean your boots between sheds until the vet has advised.
- Do not start an antibiotic on your own, because the vet needs to know what has been given before the post-mortem.
Our guide on treating a sick chicken lists the notes that help the vet most. If the vet confirms IBH, the treatment is mostly supportive. The priority is to keep the flock calm, the water clean and the feed fresh, while the vet decides on any secondary infection.
What one bad week costs a broiler house
Take a 400-bird Cobb 500 house as the example. At GH₵20 a chick, that is GH₵8,000 before feed, heat and labour. Suppose four percent of the birds die in a sudden week at the end of the third week, which is 16 birds at GH₵20 each. That is GH₵320 in chicks alone, and the feed those birds ate, plus the extra labour, is extra on top.
The number that hurts more is the time. A flock that loses birds in week four is also behind on weight at market, and every day of delay costs feed and house space. These are made-up numbers, but do the sums with your own flock before deciding how much to spend on clean feed and a proper vet visit. You can see current starting prices on our prices page, and our broiler day-old chicks page explains which breeds we keep in stock. If you are comparing broiler lines before the next batch, the breeds page sets them side by side. Plan the next batch with us on WhatsApp at +233 24 915 1503, or through the order form.
A checklist for the grower phase
Most IBH losses we hear about come after the first week, when the house is starting to look settled and the farmer relaxes. Keep this list running until the birds go to market.
- Ask the supplier what the parent flock was vaccinated against before the chicks arrive.
- Keep the feed in a dry store, and check each sack for mould before it goes into the bin.
- Walk the house twice a day and watch for huddling, ruffled birds and a cluster of deaths.
- Keep the drinkers clean and the water flowing, so the birds do not share dirty water.
- Adjust the house temperature gradually, and avoid sudden heat or cold swings.
- Keep visitors and their vehicles away from the house during the grower phase.
- Record every death with the age, the time and the signs, so the vet can see the pattern.
- Call the vet early, before the deaths add up, and keep a few fresh carcasses for the post-mortem.
More answers on flock health and ordering are on our FAQ page.
Questions farmers ask
What age does inclusion body hepatitis usually affect?
Broilers around three to six weeks old are the most often affected. Young birds can be hit too, and older birds may show milder signs. The risk peaks when the maternal antibodies have faded and the birds are growing fast.
Is inclusion body hepatitis the same as Gumboro?
No. Gumboro is a different virus that damages the bursa, an immune organ, and it causes different lesions. The two can occur in the same flock, and a flock hit by Gumboro may be more open to adenovirus infection. A vet can tell them apart at post-mortem.
Can I treat IBH with antibiotics?
Antibiotics do not kill viruses. They may be needed for secondary bacterial infections, but your vet should decide that after diagnosis. The main work is supportive care, clean water and fresh feed, plus reducing stress while the flock recovers.
Does the hatchery vaccinate against adenovirus?
Not in the programme we give your chicks. The vaccines we give cover Marek's, Newcastle, Gumboro, infectious bronchitis and coccidiosis. Ask your supplier about the parent flock, and ask your vet whether a separate plan makes sense for your area.
How do I know if mouldy feed is the cause?
Look at the feed and the store. Mould, clumps, a musty smell and damp sacks are warning signs. Your vet can test the feed and look at the liver at post-mortem, because mouldy feed and IBH can look alike in the bird.
Can I keep my birds alive by moving them to a new house?
Moving birds can spread the virus, not stop it. Do not move affected birds until the vet has advised, and never move them into a clean house without cleaning the old one first. A clean, dry, well-ventilated house matters far more than the move itself.
Is IBH a risk for layers as well?
Yes, although the age and the pattern can differ. Layers can show liver signs and a drop in performance too. Keep the same hygiene and feed checks, and ask your vet about the parent flock and the timing of any vaccines.
