Sour Crop in Chickens: Cause, Treatment and Prevention

If you own backyard chickens, you have probably heard of the sour crop in chickens. It’s one of the common problems in poultry farming. While it isn’t a highly infectious disease that affects the entire flock, it is still best to know the sour crop in chickens’ cause, treatment, and prevention.

What is a Chicken Crop?

Before getting into the details about the sour crop in chickens’ cause, treatment, and prevention, let’s first know what a chicken crop is and how digestion in birds works. Doing so gives you a clearer understanding of this health issue and better knowledge about your flock.

A chicken crop is a unique part of chicken anatomy serving food storage in the bird’s digestion process.

Where can you find the chicken crop?


Hold your chicken and point to the right of its breastbone. That is where a chicken crop is located. This body part is vital in how your chickens ingest and digest food.

The Digestion Process in Chickens

Like humans, the digestion process in chickens starts when they take in food using their mouth or beak. Since chickens do not have teeth, they use their tongue to move around food before swallowing it. Enzymes help in breaking down pieces for easier digestion.

Food travels into the esophagus from the mouth, which serves as the pathway between the mouth and the crop.

It then lands on the crop, the holding area for food, as chickens typically digest their food overnight. Imagine it as a pantry that temporarily stores food while your chicken does activities throughout the day.

You know your chicken’s crop is full when it looks like a lump near its breastbone. The softened food in the crop is then moved further into the proventriculus or gizzard.

As the food goes into the walnut-sized gizzard, more enzymes are added, where tiny stones and grit turn food into a paste. After which, this paste is passed onto the small and large intestines, where nutrients are absorbed.

After all the digesting, it turns into waste released out of your chicken’s body through the cloaca.

To visualize the chicken’s digestive tract, watch this video:

What is Sour Crop in Chickens?

As its name suggests, sour crop in chickens is a health issue that affects the crop. The crop has bacteria for breaking down food to aid in digestion.

When there are too many bacteria in the crop, typically yeast, sour crop in chickens occurs.

Sour crop is a common problem when raising backyard chickens. Don’t fret, though, as it is not contagious and will not affect the entire coop. However, you still need to address it right away to avoid complications.

Sour Crops Symptoms

Apart from playing an important role in digestion, the crop also tells you about the health condition of your chicken.

The crop is usually packed at night because of digestion that happens at that time. A frequent empty crop would tell you that your chicken has not been eating enough.

In the same way, a crop that is still full in the morning would tell you that your chicken may have digestion problems, including sour crops.

Two significant signs help you determine sour crops in chickens: the crop condition and a foul odor. On top of these two, there are also other tell-tale signs of sour crops that you should look into.

sour crop chicken

Full and Squishy Crop

The best way to check if your chicken has a sour crop is to carefully feel it in the morning. A typical crop is supposed to look empty, as food should have been digested the night before.

If you feel it is still full and looks swollen, check if it is hard or soft. A full yet squishy crop would mean your chicken has a sour crop. If it feels full but hard, it might be an impacted crop.

Chicken owners confuse these two sometimes. The comparison in the latter part of this article will help you distinguish one from the other.

Foul Odor

Another sign of a sour crop is a foul odor released by your chicken.

Smell near their beak, and if you can detect a sour odor similar to fermentation coming from the crop, then most likely, your chicken has a sour crop. The overabundance of yeast causes this smell.

Other symptoms

While the two aforementioned signs will tell you directly about sour crop in chickens, you may not instantly notice these warnings. Other common symptoms may point to sour crops.

The following symptoms may show up in chickens who may have suffered from sour crops for some time already:

  • Lack of energy
  • Unusually less physical activity
  • Lethargy
  • Diarrhea
  • Loss of appetite
  • Weight loss

Why Did My Chicken Get a Sour Crop?

how to treat sour crop

The first thing that would probably come to mind when chicken farmers find sour crop in chickens is: Why did my chicken get sour crop?

In a nutshell, an overgrowth of the bacteria leads to sour crops. Many factors and triggers lead to this abundance of yeast.

Knowing these lets you address the problem immediately and prevent it from happening again.

Slow Digestion

Not all chickens are the same – some digest slower than others. Some chickens have a slower pace when emptying their crop during digestion.

When the crop is not emptied frequently due to slow digestion, the remaining food inside the crop gets fermented, which leads to this abundance of yeast, thus, a sour crop.

Undigested Food and Items

Another reason why a sour crop occurs is when food or other items remain stuck in the crop. Food such as long, stringy grass or too much bread and pasta might be hard to digest. These will get stuck in the crop and trigger yeast growth.

Similarly, other household items can also cause this problem. Small items such as plastic and rubber that chickens swallow by accident are difficult to digest and might also get stuck in the crop.

Internal Injury

Chickens sometimes fail to recognize household items and ingest them. In mild cases, the problem would only be how slow their bodies could digest these items.

However, there are cases wherein items that are not supposed to be eaten, such as nails, rubber, and sharp pieces, injure your chicken’s body internally.

This internal injury will disrupt the body processes of your chicken, including its digestion which may result in a case of the sour crop, among other problems.

chicken sour crop

Moldy and Rotten Food

A good and balanced diet keeps health problems away. On the other hand, moldy and rotten food will bring in many problems, including sour crops.

The molds in rotten food can affect the pH balance in your chicken’s crop. This change in pH balance can cause yeast to grow and lead to sour crops.


When chickens get sick or suffer from an infection, antibiotics are part of the course of treatment veterinarians advise.

The thing about antibiotics is that they are formulated to kill bacteria that cause illness or infection. Sometimes, good bacteria get affected in the process.

When antibiotics kill good bacteria, the balance of microflora in your chicken’s body can get disrupted. This disruption may create an environment that allows for the overgrowth of yeast in the crop.

Poor Sanitation

Cleanliness is as important as your chicken’s diet. Dirty coops and living quarters can cause worms in chickens.

These worms can affect the digestive tract of chickens and cause sour crops. [How to Clean a Chicken Coop – When, Why, and How Often]

Sour Crop Treatment

Sour Crop Treatment

Sour crop is one problem you should address immediately for the condition to not worsen. There are different treatments that you can do at home. Always do this cautiously so as not to harm your chicken or cause further damage.

However, home remedies are recommended to alleviate symptoms only. The best action is to seek the advice of your veterinarian.


First, put your affected chicken in another area, preferably quiet and comfortable. It’s to avoid stressing out your chicken and the rest of the flock when doing the treatment.

Limit Food and Water Intake

Limit intake by not giving your chicken food and water for 24 hours so the crop will be emptied naturally. Limiting food and water can be used as a way to temporarily treat sour crop in chickens. When limiting food, it helps slow down digestion thereby increasing chances of healing while allowing whatever causes illness to be cured.

Try Apple Cider Vinegar

Put apple cider vinegar in a syringe and give the liquid to your chicken through the side of the beak. After 12 hours, give lukewarm water and a small amount of soft solid food.

Keep an eye on your chicken to see if the sour crop returns. Should your chicken feel better, you can gradually increase its food and water intake until it gets back to normal.

If sour crop continues to occur, inform your vet instantly so that medication can be prescribed.

Sour Crop Prevention

Sour Crop Prevention

Prevention is better than cure, saving you the hassle and stress of dealing with sour crops. To avoid sour crops in chickens, you must ensure they get the best diet and living conditions.

Maintain Clean Food and Water

Always prepare fresh water for your chickens to drink and clean food. Check your chicken feed regularly to ensure that there are no molds. Also, ensure that the natural food and table scraps you offer to your chickens as treats are safe to eat and easy to digest.

Since chickens enjoy scavenging, check your area regularly. Clear it from debris, plastic, rubber, and other items your chicken might accidentally eat. It is also essential to keep your space clean. Good sanitation goes a long way!

Give Your Chickens Some Grit

Grit is made up of small, hard particles such as stone or oyster shells that chickens swallow along with their food. These abrasive materials help grind down and digest the tougher grains they consume, which occurs in their gizzard. When your chicken eats its feed containing insoluble grit pieces, instead of biting chunks off directly, it passes into the bird’s gizzard.

As sour crop happens when there’s poor digestion, the constant grinding stimulated by ingesting gritty foods effectually prevents these conditions from turning serious. Grit should be provided regularly for healthy flocks!

Sour Crop vs. Impacted Crop: A Comparison

An impacted crop is another problem involving your chicken’s crop. Because it affects the same body part, people mistake sour crops for impacted crops.

Below is a quick comparison to guide you in distinguishing one from the other.

Watch this tutorial on how to clear the blockage of an impacted crop:

  Sour crop Impacted crop
Cause Overgrowth of yeast in the crop Food debris and items stuck in the crop
Crop condition Full and squishy, content feels like liquid Full and elongated, content is solid
Treatment Emptying the crop if the case is mild, give medication as advised by the veterinarian Lubricating the crop to dislodge the stuck food/debris


Sour crop in chickens is a problem caused by the overgrowth of yeast in a chicken’s crop. It can easily be prevented and treated. As a chicken owner, know the sour crop in chickens’ cause, treatment, and prevention to know what to do when the problem arises in the future.

Leave a Comment


Chicken Scratch The Foundry is the ultimate destination for you to learn about chicken breeds and improve your chicken farming skills. Explores the world of chickens from raising chicks to collecting eggs, Learn about different chicken breeds and discover the happy raising chicken tips.