Sudden Death

It can be very traumatic as a backyard poultry keeper when you leave you chickens happy and healthy in their coop and run only to return later and find one of them has unexpectedly died.  Sometimes there is an obvious cause like an attack from a predator or a really old hen that most likely died from natural causes and sometimes there might be nothing visibly wrong with the bird at all. 

In these cases, it is worth doing some further thinking and investigation in case it was caused by something that could impact other birds in your flock. This section will walk you through the basics of investigating the underlying cause.

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Protecting Yourself

Never handle a dead chicken with your bare hands.  Use nitrile gloves (which can be purchased from most pharmacies and home-improvement stores to have on hand) or if you are absolutely stuck, you can use double-bagged plastic grocery or rubbish bags as makeshift protection.  

It is also a good idea to wear a face mask in case you stir up droppings, dirt, or dust that could contain harmful bacteria you definitely don’t want to risk breathing in.

Investigating the Cause of Death

The following section will walk you through the five main steps for investigating the cause of death for your bird(s).

1. Examining the Affected Bird(s)

The best way to get an answer is having your veterinarian perform a post-mortem examination or necropsy.  Similar to the autopsies that are done on people to work out the cause of death, your veterinarian will be able to thoroughly check everything inside and out as well as submitting samples for further testing if visual inspection alone did not reveal an obvious cause.  While a formal post-mortem examination may be expensive, it is worth doing especially if several birds in your flock have died suddenly.

If you are not too squeamish, you can also try a simple post-examination yourself at home.  Here is a good YouTube video that walks you through the process:

2. Examining Your Other Birds

Whether just a quick glance or a full physical exam, you should check other members of the flock for any signs of illness.  Just make sure you have washed your hands and changed your clothes after handling the dead bird.  Some things to look out for:

  • Attitude: Make sure everyone is bright, alert, and active
  • Appetite: Check that they are eating and drinking normally
  • Beaks and claws: Look for blood that could indicate they were bullying the dead bird
  • Movement: Check for limping or abnormal gaits
  • Feathers: Look for signs of parasites, breakage, or ruffling
  • Vents: See if there are signs of diarrhoea, vent pecking, or prolapse
  • Eggs: Make sure that the flock is producing the expected number of eggs and the eggs are normal size and shape

3. Examining the Coop and Environment

With all the other birds out of the coop, have a thorough look through to find clues:

  • Perches or roosts: Look for blood spots that could indicate fighting
  • Droppings: Examine the droppings under the roost for blood, worms, or diarrhoea
  • Windows, vents, and doors: Look for evidence of draughts
  • Air quality: Get down to bird level and sniff the air for signs of ammonia
  • Floors and walls: Check for gaps that could let a predator in
  • Feeder: Make sure there is no mouldy feed and that it is not contaminated with droppings
  • Waterer: Check that the water is clear and fresh
  • Run enclosure: Look for toxic plants like nightshades or gaps that predators can get through

4. Protecting Your Remaining Chickens

Even if you are not sure what the cause of death is, there are some additional steps you can take to protect your birds:

  • Clean the coop: Dispose of any litter or bedding that was in contact with the dead bird and ideally, clean the coop with a sanitiser before letting other birds back in
  • Change the feed and water: Just in case it was something your bird ate, empty and clean the feeder and waterer before refilling them with fresh food and water.
  • Patch any gaps: If there were any holes in the coop or run walls, patch these up so potential predators can’t get in.

5. Disposing of the Remains

The last thing you need to consider is how to dispose of your bird’s remains. If the cause of death was unknown, it is very important to make sure that their remains cannot be scavenged by other animals or wild birds as this can cause them to become sick.  The three most common disposal options are:

Always check your local council regulations if you live in an urban area before doing this to make sure it is allowed. The remains should be buried at least 0.5 m underground with large stones placed on top to prevent other animals from easily digging up the remains. Do not bury the bird near any wells, ponds, or creeks since this can contaminate the water.

Most veterinary clinics will be able to arrange for the body to be cremated in either a group cremation, where you don’t get the ashes back, or a private cremation, where the ashes are returned in a box for you to either keep or scatter. There is a cost associated with this, and it can be expensive if there are multiple birds.

If the death was caused by natural circumstances, you can bag the remains with several layers of plastic bags to prevent smell and stop animals from scavenging the remains.

Another option is burning the remains in a fire pit or wood pile, which is effective at killing off any harmful infectious pathogens or parasites but has an unpleasant smell. Larger poultry farms use composting, but this is again not an ideal option for backyard poultry keepers because of the smell and the risk of pathogens escaping into the soil.

Common Causes of Sudden Death

Backyard poultry are very good at hiding signs of illness and it’s possible for them to have diseases that could lead to sudden death without any warning.  If you haven’t already done so, check out our Preventive Care guides to make sure your birds have the right conditions and care to prevent things from going wrong as much as you possibly can.

The following lists the most common causes of sudden death.  Most of these can only be diagnosed be performing a post-mortem examination to look at what’s going on inside the bird. If your veterinarians is performing the post-mortem examination, they can collect samples for additional testing to help confirm a cause.

Environmental Causes

Birds are very sensitive to high temperatures because they cannot sweat.  If it was a particularly hot day, your bird may have overheated.

Nutritional Causes

While most birds will generally only eat what they need, it is possible for them to become overweight if they are fed too much high calorie food.  This causes them to build up excess fat in their liver and their abdomen, which weakens the tissue structure. All it takes is some kind of stress like hot temperatures, being in peak egg laying season, or exposure to mycotoxins in mouldy foods to cause blood vessels in the liver to rupture and the bird to bleed out. 

On post-mortem examination, you would expect to see a very yellow liver and a large blood clot in the abdomen.

There are numerous things that are bad for birds to eat:

  • High calcium in pullets: Feeding layer diets to pullets can damage their kidneys and cause them to die of renal failure usually around 18 to 20 weeks of age when their bodies are stressed due to the demands of starting egg production.
  • Nightshade plants (tomatoes, potatoes, peppers): Eating the berries and cuttings from these plants can cause rapid death in poultry.
  • Pesticides and Insecticides: These are bad for bugs and also bad for your birds.
  • Herbicides: Chemical that are used to kill weeds or grass

Sometimes birds can eat something that goes down the wrong pipe and blocks their air circulation.

On post-mortem examination, you would expect to see something lodged in their trachea.

If birds eat too much too quickly, it can cause their crop to become enlarged.  This may put too much pressure on the lungs and heart, stopping the bird from breathing oxygen and circulating blood. 

On post-mortem examination, you may see a very enlarged crop.

Health Causes

Heavy burdens of internal parasites can cause intestinal obstruction, severe anaemia, and severe dehydration which can lead to death.

On post-mortem examination, there may be visible worms in the gastrointestinal tract or inflammation of the lining of the gastrointestinal tract.  A faecal examination can be performed to see if the bird had high burdens of coccidia.

Severe infestations of mites and lice can cause anaemia and possible death if the burdens are heavy.  Some younger birds may also develop secondary skin infections because of the inflammation and irritation of their skin, which can also lead to death.

On post-mortem examination, you can see evidence of mites, lice, and eggs particularly around the base of the feather shafts.

In chickens that have damage to their oviduct, the egg yolks can end up going into their abdomen instead of passing through the rest of the reproductive tract to form an egg. The build-up of egg yolks in the abdomen can cause the abdomen to swell up and make it difficult to breathe. If bacteria like E. coli get into the abdomen, this can cause a severe infection, which can lead to blood poisoning and death. 

On post-mortem examination, you will find lots of egg yolks in the abdomen and signs of infection.

Egg binding is when an egg gets stuck in the cloaca when the hen is trying to lay it. Unlaid eggs can get stuck behind causing the hen’s abdomen to swell and they can also get severe constipation from being unable to pass faeces. Hens go into shock leading to sudden death.

On post-mortem examination, you will usually see the egg stuck in the cloaca and potentially the large intestine backed up with faeces.

Breathing is essential to life and any respiratory diseases the damage lung tissue or block the airways with pus and inflammation can prevent birds from getting enough oxygen. 

On post-mortem examination, you may see pus in the airways and air sacs.  Severe gapeworm infections can also lead to obstructions and death.

Birds that are weak, have poor immune systems, or heavy parasite infections that damage the gut wall are at risk of having bacteria like erysipelas, pasturellosis, and staphylococcus enter the blood stream and cause sepsis. 

On post-mortem examination, you may not see very many signs.

This viral disease most commonly affects birds that are 6 to 16 weeks of age. The virus causes tumours to form in areas such as the brain, spinal cord, eyes, and abdomen. When birds are alive, you most often notice loss of muscle control in the wings, legs, or neck and changes in the eyes/vision. Birds most often die from starvation because they can’t move around or see to eat, but sudden death can also occur. 

On post-mortem examination, you will usually find multiple tumours around the body including the liver, spleen, ovaries, kidneys, and heart.

This viral disease most commonly affects birds that around 16 to 30 weeks of age causing tumours to form in the liver, spleen, and bursa.  Once birds start showing of decreased appetite, weakness, and diarrhoea, they will usually die within a few weeks. 

On post-mortem examination, you will often see multiple tumours located around the body and sometimes an enlarged bursa or liver.

Ovarian cancers (usually adenocarcinomas) are very common in chickens and they can seed other tumours all around the abdomen.  This damages the organs and can cause a build-up of fluid in the abdomen (ascites) and congestion in the lungs.

On post-mortem examination, you will often see multiple tumours scattered around the inside of the abdomen.

Adverse Interactions

Attacks from possums, stoats, cats, dogs, and rats can easily kill your birds.

On post-mortem examination, you may see broken feathers, bruising, and wounds on the skin.

Chickens can peck each other to death if they are stressed out from overcrowding, poor lighting and ventilation, boredom, or competition for food and water.

On post-mortem examination, you may see broken feathers, bruising, and wounds on the skin.

Notifiable Diseases

There are three key infectious diseases not currently present in New Zealand that can cause large numbers of domestic and wild birds to die off very quickly.  While it is unlikely that your flock was affected by one of these, it is important to be on the lookout because an undetected outbreak could lead to the loss of millions of avian lives and millions of dollars to the New Zealand economy.

Avian Influenza

Check out this YouTube video on signs to watch out for.

Up to 100% of birds in a flock can be affected and die within a few days.  The most common signs are:

  • Lethargy and reluctance to move
  • Droopy head
  • Red/purple combs, wattles, and skin
  • Difficulty breathing
  • Discharge from nose and eyes
  • Sudden drop in egg production

Newcastle Disease

Check out this YouTube video on signs to watch out for.

Up to 100% of birds in a flock can be affected and die within a few days.  The most common signs are:

  • Lethargy and reluctance to move
  • Shaking and tremors
  • Twisted and tilted head and neck
  • Paralysis of wings or legs
  • Uncoordinated movements

Infectious Bursal Disease

Check out this YouTube video on signs to watch out for.

Greater than 60% mortality in chicks under 6 weeks of age. The most common signs are:

  • Watery or white diarrhoea
  • Huddling or hunched over on the ground
  • Decreased appetite
  • Lethargy and reluctance to move

If you Are worried about a Notifiable Disease…

If you suspect a notifiable disease in poultry or other captive birds, you must report it immediately to the MPI Disease Reporting Hotline by calling:

 

0800 80 99 66

.

An experienced incursion investigator will ask you some questions to determine whether it may be a notifiable disease and if needed, provide additional support to further investigate the cause.

Although you may worry about being the person who found a notifiable disease, it is much worse to be the person who missed it.