Sour Crop and Impacted Crop in Chickens: Signs, Causes and Treatment for Ghana Farms

A farmer from Bawjiase drove to our Kasoa hatchery one Tuesday morning with a Lohmann Brown hen wrapped in a cloth. The bird had stopped laying, her breath smelt like spoilt palm wine, and there was a soft, sloshing lump at the base of her neck the size of a small orange. He was convinced it was Newcastle disease and wanted to know whether the whole flock would die. It was not Newcastle. It was sour crop, and by the time he left he understood what had gone wrong: a broken drinker two days earlier, a hen that had gone thirsty, then gorged on dry mash and long grass once water was restored.

Crop problems are among the most misunderstood conditions on Ghanaian poultry farms. Because the crop sits right where a farmer can see and feel it, a swollen crop gets noticed quickly, but it is often treated as a mystery illness or, worse, ignored until the bird wastes away. The truth is more manageable. The crop is a storage bag, not a stomach, and nearly every crop problem comes down to one of two things: food that has stopped moving out of the bag (impaction) or food that has sat in the bag long enough to ferment (sour crop).

This guide is written for the small and medium farmer who wants to check a bird properly, decide which problem they are looking at, manage it sensibly at home where that is appropriate, and know when a bird needs a veterinarian. It also covers the causes we see most often in Ghana, because a crop problem in one hen is usually a management warning for the whole flock.

What the crop actually does

The crop is a thin-walled pouch of the oesophagus that sits on the right side of the lower neck, just above the breast. A chicken has no teeth and eats fast, so the crop lets a bird fill up quickly and then process the food gradually. Feed collects there, softens with water and a little mucus, and is released in small amounts down to the proventriculus (the true glandular stomach) and then to the gizzard, where it is ground against grit. In a healthy laying hen the crop fills during the day and should be almost completely empty by dawn after the overnight fast.

That last point is the single most useful diagnostic fact in this article. Feel a hen's crop first thing in the morning before she has eaten. If it is still full, something is not moving. Crop problems are almost always a symptom of slow emptying, and the reasons for slow emptying range from the trivial (too much long grass) to the serious (Marek's disease affecting the nerves that control the gut, or a tumour blocking the outlet).

Sour crop: fermentation and yeast

Sour crop, called crop mycosis or thrush in veterinary texts, is a yeast overgrowth in the crop, most often Candida albicans. Candida lives in small numbers in the gut of every healthy bird and only becomes a problem when the crop contents sit too long, when the natural bacterial balance is upset, or when the crop lining is damaged. Feed that stays in a warm, wet pouch at 41 °C starts to ferment within hours. The yeast multiplies, the contents turn to a foul, gassy liquid and the crop wall becomes thickened and coated with a whitish, cheesy layer that a vet will see at post-mortem.

The signs are distinctive once you know them:

• A soft, squishy, water-balloon crop that stays full in the morning.
• A sour, yeasty or vinegary smell from the beak. Gently open the mouth and sniff; the smell is unmistakable.
• Liquid dribbling from the beak if the bird lowers her head, or when you pick her up.
• Reduced appetite, weight loss over days, pale comb, dull feathers, sometimes a drop in lay.
• Occasionally white plaques in the mouth, which you can see if you open the beak in good light.

The common triggers we see in Ghana are prolonged courses of antibiotics in the drinking water (which kill the good bacteria that keep yeast in check), feed that was already mouldy or wet, birds drinking from stagnant puddles in the rainy season, and any underlying slowdown of the crop. A hen that has had impaction for two days will usually develop sour crop on top of it. Very hot weather also plays a role: birds drink enormous volumes during a Kasoa afternoon and eat little, so the crop contents become a warm soup.

Impacted crop: the blocked bag

Impaction is a physical blockage. The crop fills with material that cannot pass through the narrow outlet into the proventriculus, so it hardens and stretches. Feel the crop and it is firm, doughy or even rock-hard, often larger than a hen's egg, and it does not shrink overnight. The bird may keep eating in the early stages, making the mass bigger, then stop eating altogether as the stretched crop becomes painful. Some birds stretch their necks repeatedly and gape, trying to shift the mass.

What causes it in Ghana:

• Long, tough grass and weeds. Free-range or semi-intensive birds released onto a compound after the first rains graze on long elephant grass and guinea grass. The fibres tangle into a ball. This is the number one cause we see from March to June.
• Feed sacks, twine and string. Birds swallow strands from torn polypropylene feed sacks. A ball of twine in the crop will never digest.
• Dry mash eaten fast after thirst. A bird that has gone hours without water and then eats dry mash creates a concrete-like mass, especially if water is still short.
• Litter eating. Chicks and pullets on fresh wood shavings, or on sawdust, will eat litter if feed is late. Fine sawdust is the worst, because it packs.
• Grit shortage. Birds without access to grit cannot grind fibrous food in the gizzard, so material backs up.
• Foreign objects. Nails, small stones, plastic pieces and even coins turn up in crops at post-mortem.

Left alone, a large impaction stretches the crop wall permanently. This is the origin of pendulous crop, where the pouch hangs like a loose bag below the neck and never empties properly again. A pendulous crop bird is a repeat sour-crop patient for the rest of her life, which is why acting early matters.

How to examine a bird step by step

Take the bird off feed for one night and examine her at dawn. Hold her against your body with one arm and use the free hand to feel the right side of the lower neck. Work through this checklist:

1. Size. An empty crop is barely there. Anything larger than a golf ball after an overnight fast is abnormal.
2. Texture. Squishy and sloshing points to sour crop. Firm and doughy, or hard, points to impaction. Mixed texture (a hard core with fluid around it) means an impaction that has gone sour.
3. Smell. Open the beak. A sour or yeasty smell confirms fermentation. A crop that smells of nothing much is a clean impaction.
4. Mouth. Look for white plaques or thick mucus.
5. Whole-bird check. Weigh her or feel the keel bone. A sharp keel means she has been losing condition for days. Check droppings: watery green droppings suggest she has not been eating solids.
6. Flock check. Look for the cause. Walk the run for long grass, check feed sacks for tears, check drinkers, check litter. One crop case is often the first of several.

Managing sour crop at home

Mild sour crop in an otherwise bright bird can be managed on the farm, but check with your veterinarian first, particularly if the bird is valuable or if you have several cases. The principles are simple: stop the fermentation, get the crop moving, and restore normal gut bacteria.

• Isolate the bird in a clean, shaded cage with fresh water only for the first 12 hours. Do not give feed while the crop is full of liquid.
• Acidify the water. Yeast dislikes an acid environment. Many farmers use a splash of apple cider vinegar or a commercial poultry water acidifier in the drinker for the isolated bird. Follow the product label; do not use metal drinkers with vinegar.
• Gentle massage downward from the top of the crop, several times a day, with the bird held upright, to encourage emptying. Never squeeze hard.
• Restart feeding carefully. Once the crop has begun to shrink, offer small amounts of soft, easily digested food: wetted layer mash, mashed boiled egg, a little plain yoghurt if available. No grass, no whole grains, no litter access.
• Probiotics. A poultry probiotic in the water helps re-establish the bacteria that keep Candida in check. Our article on probiotics and gut health explains what to look for.

Severe or persistent sour crop needs a veterinarian. Antifungal medication (nystatin is the usual choice in poultry) is prescription-only in Ghana and dosing must be by body weight. A vet will also look for the underlying reason the crop slowed in the first place. Do not put antibiotics in the water to treat sour crop. Antibiotics do nothing against yeast and will usually make the problem worse by clearing out the last of the helpful bacteria.

Managing impacted crop

A small, fresh impaction sometimes responds to conservative treatment. Withhold feed, provide water freely, give a few millilitres of warm water or a little vegetable oil by mouth (dripped slowly into the side of the beak, never squirted), then massage the mass gently for several minutes to break it up. Repeat every few hours. Some farmers add a little olive oil or coconut oil to soften fibre. If the crop shrinks over 24 to 48 hours and the bird begins to pass normal droppings, offer soft food and keep her away from grass for a week.

Warning signs that the impaction is beyond home care: the mass is hard as a stone and does not change with massage, the bird has stopped drinking, she is losing weight fast, or she has been like this for more than two days. At that point a veterinarian can perform an ingluviotomy, a small surgical opening of the crop to remove the mass. It is a straightforward procedure in skilled hands and birds usually recover well. The alternative for a low-value bird is humane culling; a bird with a permanently blocked crop starves slowly, and that is worse for the bird and pointless for the farmer.

Orientation only. Any medication (antifungal, antibiotic, or otherwise) should be prescribed and dosed by a qualified veterinarian, and label withdrawal periods followed for eggs and meat.

Why crop problems cluster on certain farms

A single hen with a crop problem is bad luck. Three in a month is management. When we visit farms that keep reporting crop cases, the same patterns come up, and they are worth walking through honestly.

Water interruptions. Bell drinkers that block, nipple lines with airlocks, a borehole pump that fails during dumsor: any period without water followed by a rush of dry feed is a recipe for impaction. Read our guide on clean water for poultry and check drinkers twice daily, not once.

Reliance on water antibiotics. Some farmers put a broad-spectrum antibiotic in the water "as prevention" every few weeks. This is bad practice for many reasons, and yeast overgrowth is one of them. If your birds are healthy, they do not need antibiotics. If they are sick, they need a diagnosis. See antibiotics in poultry for the responsible approach.

Mouldy or wet feed. Feed stored on the floor during the rainy season absorbs moisture, grows mould and delivers both mycotoxins and a ready fungal load into the crop. Mycotoxins also damage the crop lining directly, which is one more door open for Candida. Proper feed storage is a health measure, not just a cost measure.

A mini case from the Central Region

In May last year a farmer near Awutu Breku with 300 Sasso birds on deep litter and a fenced run called us about "birds with goitre". Six had large crops, two had already died. When we visited, the run had not been cut since the rains began and the grass was over half a metre high. On top of that, feed had run out for a day the previous week, and the birds had been released to forage. The post-mortem on one dead bird showed a crop packed solid with grass fibres and a secondary sour crop with a thick cheesy lining. The four living birds with impaction went to a vet in Kasoa; two were operated on and recovered, two were culled. The farmer slashed the run, restarted feed, added grit, and had no further cases. Nothing exotic, just water, feed continuity and grass length.

Prevention checklist

• Check that every drinker delivers water twice a day, morning and afternoon. A bird must never be thirsty long enough to gorge afterwards.
• Provide insoluble grit (crushed granite, not oyster shell) from about three weeks of age for any bird with access to fibre.
• Keep runs slashed to ankle height. Rake up cut grass; do not leave long clippings for birds to eat.
• Store feed off the floor on pallets, in a dry room, and discard anything mouldy or clumped.
• Do not medicate healthy birds. Use antibiotics only on veterinary advice for a diagnosed problem.

Frequently asked questions