PHOTO: Photos by Kathy Shea Mormino
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April 15, 2019

Most keepers of backyard chickens don’t have the luxury of access to poultry veterinarians to care for their feathered friends. As a result, most education about chicken health, anatomy and medical issues comes from the Poultry School of Hard Knocks.

We do our best to care for our chickens by reading poultry care books, scouring the internet for reliable information and comparing notes with fellow keepers about things we see or feel—and things we hope we never see or feel. However, some lessons present themselves most unexpectedly, and chief among them is Crop 101.

New chicken-keepers commonly stumble upon the crop when they pick up a chicken and one of two things happens: They’re either convinced that they have found a sizeable tumor, or they unknowingly squeeze it, causing the bird to vomit.

So, what exactly is the crop, where is it located, what does it do and what could possibly go wrong with it?

chicken anatomy health crop


Crop Function

The crop—also sometimes called the “craw” in the South—is an expandable, albeit weak, muscle underneath the skin located slightly to the right of a chicken’s breastbone at the bottom of its neck. It acts like a vest pocket for the temporary storage of food.

When a chicken picks up food with its beak, its tongue pushes the food to the back of its mouth into the esophagus, which is like a water slide from the mouth to the crop. Once there, the food mixes with small amounts of beneficial bacteria and lactic acid before moving farther along the digestive tract to be broken down for more processing.

Why does a chicken have a special food storage pocket at all? The answer relates to the chicken’s unenviable status as a prey animal. Chewing food is time-consuming, and the more time spent in open fields or pastures foraging and chewing, the greater the risk of being located and eaten by a predator.

The crop is part of a digestive system that lets chickens ingest food quickly, stash it in this take-out container and break it down into smaller pieces after having reached a safe location. One might say the chicken is the original fast-food consumer.

What’s Normal? What’s Not?

It’s important to know what a normal crop feels like when it’s full and when it’s empty, so you can identify a problem when there is one. An empty crop is not ordinarily palpable. To feel a normal, full crop, identify a bird that you know has eaten recently and pick her up with her tail facing you and beak facing away from you. A hen sitting in a nest box is an easy target for this purpose.

Next, reach around to the front of her breast, slightly to the right of the keel bone. If you can’t feel anything, you’re probably in the wrong spot. You might be too high up on the neck.

A normal crop feels swollen and slightly firm after a bird eats, but it shrinks as food is digested. It can be normal for some birds’ full crops to be visible. I find this to be true in my more voracious flock members.

If you ever question whether a particular chicken’s crop is emptying properly, remove food and water from the flock members after they have gone to roost for the night. Before replacing the food and water first thing in the morning, feel the bird’s crop. It should be empty. If it’s not empty, there is a problem.

Several abnormalities backyard chicken-keepers can encounter and should be able to recognize are impacted, sour and pendulous crop.

Impacted Crop

After a normal night of fasting, if the crop feels full, hard or squishy like a water balloon in the morning, it might mean food or other fibrous material such as straw, long strands of grass or string is stuck inside. This is a condition known as impacted crop.

Laying hen veterinarian Mike Petrik recommends flushing it with water to loosen the impaction, which can be a little tricky for the average backyard chicken-keeper, as there is a risk of forcing liquid into the bird’s airway. It’s always best to consult a veterinarian for such a procedure.

Never attempt to force a chicken to regurgitate the contents of an impacted crop. If a mass of tangled stuff is lodged in it, turning a bird upside down will not dislodge the mass but will make the chicken feel worse.

With a severe impaction, the blockage can cause swelling that ultimately suffocates the bird, in which case surgical removal of the offending material is necessary.

chicken anatomy health crop

Sour Crop

Sour crop, also known as thrush, crop mycosis or a yeast infection, is a fungal infection. Bad breath is generally the first sign of this; there should never be a yeasty or foul odor coming from a chicken’s beak.

Despite what you might have read or heard, a bird with sour crop should not be forced to regurgitate repeatedly by turning it upside down. Emptying the crop’s contents of liquid will not cure the fungal infection. Further, the act of vomiting can kill the bird if fluid gets into her windpipe.

The treatment I would use is detailed below. It involves cleaning and sanitizing the flock’s feeders and drinkers, isolating the affected bird and flushing the crop with a specific Epsom salt solution, followed by a specific course of antifungal medication.

Sour Crop Treatment

[This treatment was adapted, with permission, from The Chicken Health Handbook, 2nd edition, by Gail Damerow.]

Copper sulfate is commonly used to treat a chicken with sour crop, but an overdose is toxic. To avoid overdosing, first prepare a solution by mixing 1⁄2 pound copper sulfate plus 1⁄2 cup vinegar into 1⁄2 gallon of water. Clearly label this container as your stock solution. To each gallon of the chicken’s drinking water, add 1 tablespoon of stock solution.

First, flush the bird’s digestive system with Epsom salt.

Mix 1 teaspoon Epsom salt dissolved in 2 tablespoons of water. Gently pour or squirt this solution down the bird’s throat twice daily for two or three days, or until the bird recovers.

Then feed as usual, while using the stock solution to treat the chicken’s drinking water until the infection is under control. During this time avoid using any antibiotics, which will make the condition worse. As a follow-up treatment, nystatin oral antifungal may be helpful, as may also a probiotic used to restore normal crop bacteria. (Poultry suppliers offer probiotics formulated specifically for chickens).

Adding vinegar to the drinking water at the rate of 1 tablespoon per gallon—double the dose if the water is alkaline—can help prevent a recurrence of this infection in two ways: by discouraging the growth of candida in the drinking water and by helping the chicken’s crop maintain a pH that encourages beneficial bacteria to compete against candida and other potentially harmful microbes. Note that adding too little vinegar to the drinker can actively stimulate yeast growth.

chicken anatomy health crop

Pendulous Crop

A crop that can no longer return to its resting size when emptied of food is called “pendulous” because it swings back and forth in front of the bird as it walks. This is uncommon in backyard chickens. I have seen it only once in my flock in nearly a decade. Because a pendulous crop has lost elasticity, it doesn’t empty its contents fully, which often results in infections from the residual food and water fermenting inside. Birds with pendulous crop can suffer dehydration, malnutrition, weight loss and ultimately death.

Genetics are a widely suspected cause; therefore, birds with this condition shouldn’t be bred. Advanced age and binge eating might be predisposing factors.

You can’t do much to prevent pendulous crop, but you might mitigate its progression. Always ensure access to clean water and fresh feed during all daylight hours to avoid overzealous gorging. If a chicken with a pendulous crop progressively loses weight or its eyes become sunken, it has become dehydrated and malnourished, and it’s time to consider end-of-life options.

Now that you’re aware of the crop’s location and function, you should be able to trouble-shoot a problem if one arises. Fortunately, crop dysfunction in backyard chickens that are cared for properly is almost as scarce as hens’ teeth.

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