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Are Your Backyard Chickens Dying? Here Are The Top Reasons Why!

As a chicken owner, there is one thing you need to prepare yourself for, even if it seems like a long time away. One day, one of your chickens is going to die. However, it may not be from old age. One moment, you are watching your hens run around the garden. The next, a hen dies. If you are losing your backyard chickens suddenly, there may be more to it than meets the eye. Figuring out those reasons for sudden chicken death is important, as it can help you keep the other backyard chickens alive.

A Study on Sudden Chicken Death

dead chicken on the earth

Backyard chickens suddenly dying is such a common thing in the United States that there have been studies on it. Between 2015 and 2017, several institutions teamed up to publish a study titled “Causes of Morality in Backyard Poultry in Eight States in the United States” in the Journal of Veterinary Diagnostic Investigation. The teams performed autopsies on thousands of birds (nearly 2,700 birds, 96% were chickens) from Hawaii, California, Georgia, Colorado, South Carolina, Texas, and Pennsylvania.

Once the autopsies were finished, it was found that the major cause of death was some kind of necropsy, or tumor. In chickens, the main cause of tumors is a virus, like Marek’s disease. About a third of the birds collected died from some kind of infectious disease. Parasites were found in 28% of the birds, and bacteria was the second leading cause of death.

But the study rooted out a few more causes that chicken keepers tend to underestimate, including environmental issues, like lack of nutrition and zero access to clean water.

Reasons Why Your Backyard Chickens Are Dying

According to studies and accounts from other chicken keepers, here are the main reasons your chickens die unexpectedly:

  • Heart attack
  • Poisoning
  • Impacted crop
  • Trauma
  • Egg-bound
  • Parasites or bacteria
  • Viruses and disease
  • Organ failure
  • Malnourishment, including dehydration

Now let’s go into the details for each of these reasons.

Heart Attack

dead chicken from avian influenza

Did you find your dead chicken laying on its back or side? In that case, they may have perished from a heart attack. Yes, chickens can suffer from heart disease, like humans. Sometimes known as flip-over disease, heart attacks affect chicken breeds with a faster growth rate, such as broilers or hybrids made for egg-laying. Broilers, like the Cornish Cross or Production Red, tend to experience rapid maturity, putting their organs under stress.


Chickens are inquisitive but not always the brightest light in the shed. Because of that, chickens tend to come across poisonous substances and foods and will eat those things, none the wiser. Rubber and plastic pieces from toys or other items are also capable of killing chickens.

If you are raising plants that are toxic to chickens, like those of the nightshade family, make sure you are keeping your flock away.

Crop Impaction

An impacted crop is exceedingly dangerous for your chickens, and you may not know it has happened until it is too late. Chickens tend to eat anything that catches their interest, even if that food is not good for them. For that reason, food, especially stuff with a lot of fiber, like straw or grass, can clog up the crop, where the food is stored.

Crop impaction does cause plenty of symptoms. You will notice lethargy, lack of appetite, and increased water consumption among affected chickens. Crop impaction can rapidly lead to things like sour crop, pendulous crop, and even death if left untreated.


Anything that could injure your chicken may potentially lead to a sudden death. Let’s say you bring in a few younger hens to a flock with an established pecking order. A fierce fight may break out. Chickens can also be trampled, pecked, and bullied to the point where the trauma is so severe, they die.

Trauma can also happen when your chicken is running away and collides with an object. Internal damage to the organs is often undetected. As such, their condition may worsen quickly, and you may never notice.

Egg-Bound Hen

chicken lying sick

Sometimes hens have difficulty pushing eggs out through their vents, resulting in egg-binding. Usually, broiler and hybrid breeds struggle with this, as their reproductive organs wear out quickly. Also, any breed that lays larger than average eggs is at risk of becoming egg-bound. Calcium deficiency and being overweight are other reasons egg-binding occurs.

Some signs of egg-binding include a swollen, distended abdomen, loss of appetite, lack of eggs, and fluffed out plumage. Unfortunately, egg-binding is not always immediately noticeable and can lead to death. The best way to prevent this from happening is to make sure your chicks are getting adequate nutrition. Provide your hens with large enough nesting boxes, as well.

Parasites and Bacteria

Often referred to as invisible illnesses, parasites and bacterial infections attack the inside of the chicken. You may not see many visible symptoms because of this. In most cases, it takes an autopsy to tell you if worms, lice, mites, or some kind of bacteria killed your backyard chickens. For example, coccidiosis is often associated with sudden death. Spread through droppings, coccidiosis can be transmitted throughout the whole flock swiftly. Another example is mycoplasma, which causes eye inflammation and sneezing.

Other bacterial diseases, such as E. coli are prevalent. E. coli will proliferate and spread throughout your flock, causing things like salpingitis (infected oviduct), coelomitis (egg yolk peritonitis), and vent prolapse.

Viruses and Disease

What is one disease that affects chickens worldwide and causes their untimely deaths? Marek’s disease. Chickens are infected with Marek’s disease the moment they inhale the virus, which is in the dander of other afflicted chickens. Thus, Marek’s disease is most pronounced when the coop is unclean and improperly ventilated. Sadly, there is no cure for this virus. So if you want to prevent it, consider getting your chickens the vaccine. The Marek’s disease vaccine is about 90% effective.

Cancer is another disease that chickens can get, particularly ovarian cancer in breeds that lay excessive amounts of eggs. Laying eggs almost everyday of the week is hard on the body. It’s believed that continuous ovulation, which is a trait only domesticated chicken breeds have, puts extreme strain on hens, increasing their risk of cancer.

There are also noninfectious diseases that may randomly pop-up. The most common disease affecting backyard chickens is hemorrhagic liver disease (HLS). If your birds are overweight or have a diet high in fats, they are at an increased risk of HLS.

Organ Failure

veterinarian applying injection to chicken

One of the most common causes of chicken death in the backyard is the sudden onset of organ failure. Among many broiler breeds and hybrids that have accelerated growth, there is a higher incidence of organs wearing out quickly. The fast growth rate, as well as increased amount of eggs laid, stresses the body.

For broilers, most of them are ready to be prepped for consumption around 8 weeks old. Any older than that, and their organs begin to fail. These chickens were simply not meant to live a long time.

Furthermore, overweight chickens often suffer from health complications that go unnoticed, including organ failure. The extra weight tends to overburden their bodies, and they die more quickly than chickens kept at a healthy weight.


There is a load of evidence — both scientific and anecdotal — suggesting that poor nutrition, lack of exercise, and limited access to water play a key role in sudden chicken death. Backyard chickens dying en masse often means that there is something fundamentally wrong with how the chickens are living. If you do not see any signs of virus, parasites, or bacteria, then you should next consider their diet.

Make sure you are feeding your chickens a high-quality feed with about 16% protein. Your chicks are going to need between 18-24% protein in their starter. If there are members of the flock that produce more than 250 eggs per year, you may want to bolster their diet with additional calcium and protein.

Furthermore, make sure your chickens have plenty of cool, clean water to drink. Chickens are about 70% water. Should the water level in their bodies drop, normal functions are disrupted. Water is so important to your chickens that even a 10% decrease in water levels could be fatal. You will know when your chickens are dehydrated by pale combs and wattles, panting, holding their wings away from their bodies, diarrhea, as well as convulsions and seizures when nearing their end of life.

Keep Your Flock From Dying

Are your backyard chickens dying? You now know the reasons are parasites, disease, organ failure, injuries, poisoning, malnourishment, and environmental issues (among others). If you do not want to wake up to any more surprises, it is best to tackle these reasons for chicken deaths head-on. Make sure you are keeping your chickens at a healthy weight, feeding them the correct amount of food, providing them a safe place to roam, and cleaning out the coop regularly. Do that, and your flock will be happier, healthier, and live until old age takes them.