Complete Guide To Sour Crop In Chickens (Identification, Treatment And More)

As backyard chicken keepers we do not think too much about a chicken’s crop.

However it is a vital piece of the digestive tract that serves as a holding place for undigested food.

In the wild, chickens have to eat their food quickly as predators might be lurking nearby. So they have a pouch (the crop) to let them store the food to digest later.

Sour crop is a common problem with chickens (especially in the springtime).

Keep reading to learn all about sour crop, what it is, how it happens and how to treat it…

Sour Crop

Chicken’s Crop & Digestive System 101

Chicken Crop Anatomy

The digestive system of a chicken is quite different from a human and it is important to know at least the basics of how it functions so you can treat problems as they arise.

For a chicken the digestion begins at the beak (mouth).

Chickens take in food, and move it around with their tongue then swallow it whole (as they have no teeth).

Digestion starts here as enzymes are added from their mouth which causes the food to start breaking down.

Food then goes down a pipe called the esophagus which connects the mouth to the crop. The esophagus is stretchy so that it can accommodate some larger pieces of food too.

The crop is a large storage pouch where food waits before it is processed in the gizzard. The crop is full of bacteria which help to break down the food while it is waiting to travel into the proventriculus. If you have seen the crop of your chickens just before they go to bed it looks like a huge lump on the right side of their breast bone. However, it only holds about 45 cubic centimeters (1½ oz) of food.

As food is processed it gradually moves forward into the proventriculus where enzymes are added and then into the gizzard.

The gizzard is really quite amazing – it is the size of a walnut but very muscular!

Within the gizzard are all the little stones and bits of grit that the chicken has eaten and uses to grind food down into paste. This area is the main area where the food is broken down for fuel.

The action of the gizzard in combination with the grit grinds down the food into a paste which then passes through into the small intestine. In the small intestine more enzymes and body salts are added to remove the nutrients from the food.

Food then passes into the large intestine where water and the last of the nutrients are removed from the paste.

Finally the food (paste residue) is moved through to the cloaca or vent where it is expelled as droppings.

The white coating on top of the poop is actually urine in the form of urates.

What Is Sour Crop In Chickens?

Chicken Dr

So what exactly is sour crop?

Simply put sour crop is a fungal infection in the crop and is caused by food that is stuck (or left) in the crop overnight. It causes the normal bacterial flora to become imbalanced and the bad bacteria have taken over a sour smell.

In a normal and healthy crop the PH is around 5.5 – this acidity helps to start breaking down the food. Bacteria thrive in this environment and do their part in the breakdown of food into usable nutrients.

If the acidity inside the crop is altered it throws the system completely off balance and certain bacteria become more prevalent and upset the delicate balance.

Candida albicans is one such entity.

This is not a bacteria but a fungus.

Whilst this sounds gross the Candida is a necessary component of a healthy crop.

Candida can proliferate into large white plaques that impair the ability of the crop to do its job efficiently. In severe infections Candida can be found in the esophagus and mouth too.

The alteration in acidity and change of bacterial flora leads to the crop slowing down and not emptying completely overnight and any leftover food will start to ferment inside the crop.

It is this fermentation process that gives the problem its name and familiar smell: sour crop.

Impacted Crop

An impacted crop is a crop that has completely stopped working due to a blockage (usually food).

Sometimes these blockages can extend into the proventriculus too – without treatment this hen will die.

You can try massaging the crop from the bottom to the top to try and break up the food and encourage movement.

Then give her olive or coconut oil three times a day using a medicine dropper.

If there seems to be no movement after 24-36 hours you should take her to the veterinary for surgery.

Just remember that an impacted crop is an emergency and is best treated by a veterinarian.

6 Things That Cause Sour Crop

Sour Crop In Chickens

There can be several things that can cause sour crop and we will examine each in turn.

Fortunately most of them are preventable and can be easily avoided.

Stringy Grass

This usually happens in the springtime or when the chicken has not had any greens for a while.

They will eat long tough strands of grass which are difficult to digest.

Pieces of long stringy grass or plant material can get balled up in the crop. It is difficult for the gut to deal with this material and it can slow down digestion and cause a blockage. Just one or two pieces can be enough to cause a problem in some chickens (especially bantam breeds).

Young pullets can sometimes get the problem by eating their bedding.


An overload of worms can impact how efficient the digestive tract is.

Different species of worms live in different areas of the digestive tract – the worm most commonly found in the crop is the thread worm.

These worms can interfere with the absorption of nutrients which can cause malnutrition. They can also cause a decrease in appetite and weight loss.

Antibiotics and Infection

If your chicken is being treated with antibiotics for an infection, then the antibiotics can alter the delicate bacteria balance in the crop.

Antibiotics are usually fairly broad spectrum meaning they will kill the good bacteria along with the bad.

The destruction of the good bacteria in the crop can lead to a buildup of bad bacteria which causes sour crop.

Also if your hen is suffering from an infection she can develop sour crop.

Often sour crop can develop as a secondary infection in a hen that is sick.

This can often become a bit of a vicious cycle.

As the infection is cured by antibiotics, the crop issue can become more severe due to loss of some of the good bacteria.


Chickens are notorious for eating anything that looks tasty, including: nails, staples and bits of wire.

These items usually pass through the system without causing problems but once in a while they can be problematic.

Anything that causes an internal injury to the crop will upset the natural order of things by slowing down the digestive process and altering the internal environment. Make sure you pick up any feed sack string, rubber bands, nails and twist ties so that your ladies cannot eat them!


As we have already discussed worms can be a big problem for chickens.

Poor sanitation and cleaning will make worm problems even worse.

You will need to keep the coop, nest boxes and areas that the chickens use as clean as possible.

If you have a dirt run or barn floor then regular raking will help to prevent the buildup of worm eggs.

Moldy Feed

Moldy feed can also be a problem.

The fungi present in moldy feed can alter the PH balance in the crop and also cause other significant problems for your chickens – never feed them anything that is moldy. You can use a chicken feeder to prevent this problem.

Sour Crop Symptoms

Vet Checking Chicken Crop

As chickens are prey animals they hide their illness well.

Fortunately there is an easy way to tell if your chicken has sour crop or not.

If you suspect they have sour crop then remove all the feed and water from the coop overnight.

There should be nothing for them to eat or drink available.

In the morning find your chicken and check her crop. It should be flat when you touch it. If it feels squishy, boggy or is visibly present, then her crop is not emptying properly.

The second telltale sign is a sour smell coming from the beak. Pick her up and put your nose right beside her beak to check – the odor of sour fermentation is unmistakable. You will likely hear a lot of gurgling from their stomach too.

Other signs of sickness will likely be present too including:

  • Weakness and lethargy
  • Hunched up
  • Loss of appetite
  • Weight loss
  • Diarrhea
  • Decreased egg production
  • Change in quality of egg shell

These symptoms will only be present if the chicken has had sour crop for a while.

Many of these symptoms are generic for a whole range of problems, but the two cardinal signs mentioned above will give you a definitive answer.

Sour Crop Treatment

Chicken Crop Treatment

There are a variety of ways to treat sour crop.

Just remember that some can be dangerous, so we have brought together the most usual and effective cures.

All of these treatments require the cooperation of your chicken. This is something that they do not usually give easily, so you may need a friend to help you out.

You will need to isolate the hen as you are going to be busy with her and you do not need to be chasing her around the barn each time you need to do something.

Also since the crop you should not give them food for the first 24 hours.

You may think this is cruel but jamming more food in her crop will not solve the problem.

Firstly you should try to massage the crop gently. Just rub and gently knead the area trying to break up or move along the contents of the crop. This action alone can sometimes cure the problem if it is caught early on. Do this a few times a day.

Epsom Salts

Epsom salts are an old time remedy.

Also known as magnesium sulfate, it can be used to help detoxify your chicken’s crop.

You should dissolve 1 teaspoon into a cup of water and give this to your chicken 2-3 times per day. You will need a syringe, towel and paper towels.

Use the syringe to give her the epsom salt solution.

You will need to wrap her in a towel and slowly drop the solution down her beak until it hangs at the tip where she will take it in. If you happen to have a very cooperative chicken, you can open her beak and deliver about one milliliter at a time.

This treatment will need to be done for 2-3 days.

Tomato Juice

There is no empiric information available on using tomato juice for sour crop.

However it has become a popular option and as it is harmless we have included it here.

You should give your chicken 1-2ml per serving and give it to them 2 or 3 times a day for 24 hours only.

It is likely the acidity of the juice can help to restore the balance in the crop and help with digestion.


Molasses can be used as an initial flush instead of Epsom salts.

If you have several chickens with sour crop and they won’t drink the Epsom salts flush then try this instead.

Mix 1 pint of molasses to 5 gallons of water and make sure they drink the water.

Do not give them this water for longer than 8 hours.

As a side note molasses can cause diarrhea so be prepared for runny poop and do not panic.

Copper Sulfate

You can use ½ teaspoon of copper sulfate per gallon of drinking water every other day for 5 days. The copper sulfate acts as a detoxifier and will help to eradicate the thrush. This should be the only drinking water available to the afflicted hen.

Please do not think more is better.

Copper sulfate can be toxic to chickens in higher concentrations.

Also do not use metal containers for this mixture as the copper can react with other metals.

Emptying The Crop

Sometimes you will need to empty some of that foul smelling fluid out of the crop to give the hen some relief.

This video is a helpful tutorial. Just make sure you wear some old clothes!


If none of the other methods worked, or the sour crop is so severe that it can be seen in the mouth then you will need to use Nystatin.

This is a prescription only medicine so you will have to talk with your veterinarian.

Sour Crop Prevention

As with all ailments, prevention is much better than the cure.

Fortunately most of the causes of sour crop are preventable and looking back to our causes list above, we have seen just how preventable it can be.

Stringy Grass

Keeping the birds away from areas with long tough grasses or weeds is the first thing you should do. Try to keep areas to which your chickens have access to trimmed down to no longer than 4 inches. Also remember that long pasture grass can hide a variety of predators, so it pays to keep it short.

Also if you cannot let your chickens free range then make sure they have enough available grit to help with digestion.


Worms can be dealt with fairly easily.

Most chicken keepers fall into one of two categories. The first folks worm regularly on a schedule and this prevents problems from starting in the first place.

The only problem with this is the rise of resistance to the medications – if you do worm regularly it is a good idea to switch around your medications once in a while.

The second group worm as necessary.

Worms are a given in most creatures including chickens. It is only when the balance is upset that worms become problematic. Recognizing when you have an issue requires keen observation and good husbandry. Fecal float tests can be done by your local veterinarian if you think you may have a problem.

Antibiotics and Infection

If your chicken is taking antibiotics just be aware that they can cause crop problems.

Whilst you generally cannot avoid giving them antibiotics you can pay close attention to any signs of sour crop.

Be extra vigilant and watch carefully for any indications of problems and treat earlier rather than later.


As we already know an injury to the crop can be very problematic.

Make sure you pick up leftovers after your yard projects – nails, screws and staples etc. When opening feed sacks make sure to get rid of the string too.

Rubber bands are another favorite!

All of these things seem to be attractive to chickens so remove them before they can eat them.


Just remember that filthy coops and runs will harbor millions of germs, worm eggs and other nasties just waiting for your birds to eat them.

You should have a regular cleaning routine for both food and excrement.

Also hose out the coops regularly to remove as much of the waste as possible.

Clean your poop boards and the floor of the coop frequently. Dusting for lice and mites will also help your chickens to stay healthy.


Well there you have it, our complete guide to sour crop in chickens.

It is a miserable experience for both you and the chicken.

Fortunately there are lots of things you can do to relieve the misery for your bird.

When found early enough it can be treated very successfully and chances are it will never occur in the same chicken twice.

Just remember that crop impaction is much more severe and requires the assistance of a professional to treat.

Let us know in the comments section below if you have any questions…

Chris Lesley Bio Picture
Chris Lesley has been Raising Chickens for over 20 years and is a fourth generation chicken keeper. She can remember being a young child when her grandad first taught her how to hold and care for chickens. She also holds a certificate in Animal Behavior and Welfare and is interested in backyard chicken health and care.


  1. Hello! I was wondering what breed of chicken you have in they pictures under sour croup symptoms and treatment and in the video on clearing the impacted crop. I have the same hens. I found very little info on them. Thank you for your time and dedication.

  2. Thank you so much for the video. I am a new chicken owner and one of my chickens indeed had sour crop.

    I followed the instructions in your video point-by-point and it worked beautifully. Thank you so much for sharing your expertise!

  3. Thank you very much for your easy and thorough information about sourcrop it’s the best I ve read as I have a hen with the problem and now feel better able to understand and treat her.

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