Crop & Gizzard Impaction in Chickens

 

By Dr Rob Marshall

 

Crop impaction is a life threatening condition of chickens with several predisposing causes.

The treatment required and outlook for recovery depends upon identifying the exact cause of the impaction and the length of time impaction has been present. .

Because crop impaction is nearly always the result of faulty nutrition, adjusting the diet to better support the egg laying process and to prevent wayward foraging behaviour is the best method to avert this serious problem.

Food supplements are required to prevent this problem in susceptible prolific egg laying breeds, such as Isa Browns, as pelleted diets do not provide them with enough nutrients to support high levels of egg production in a backyard environment where gardens soils, stones, compost heaps, garden waste with fibrous material and other contaminated areas predispose them to impaction problems.

Refer to Poultry Health Programmes that have been specifically designed to provide the additional nutrients needed by to support the egg laying process and thwart impaction problems.

 

Symptoms of Crop Impaction

 

The crop is a food storage organ and in a healthy chicken empties completely overnight.

The first signs of impaction are usually discovered during the morning feed time when a chicken is noticed to be quiet, disinterested in eating and thirsty. On closer examination, a doughy type swelling is felt in the crop indicating the crop has not emptied overnight. Immediate treatment at this time will bring about a rapid and complete cure.

The thirst of an afflicted bird will continue to increase over the next 24 hours in an effort to relieve the blockage. Often by this time the bird has lost interest in food and within another 12 hours may twist its neck from side to side in an attempt to push food through the crop. It may also open its mouth in a gaping/gasping manner. Within 48 hours of the onset of the problem advanced weight loss and fluid accumulation in a distended crop may be noticed. As well there may be a foul odour coming from the mouth and the bird is often extremely withdrawn, closes its eyes and may produce a smelly watery vomit. The outlook for recovery at this stage of the condition is far less favourable than when treatment is initiated earlier.

Immediate veterinary intervention is necessary as soon as symptoms are noticed because the impaction has already been present for at least 24 hours. The outlook for recovery is very good when treatment is given at this early stage of the condition.

Treatment includes crop flushing, fluid therapy, force-feeding, warmth and antibiotics. When treatment is delayed the condition of impacted crop rapidly deteriorates as a result of fermentation of the contaminated material within the crop. Death occurs within 2-3 days from heart failure as a result of toxaemia, dehydration and starvation.

 

Causes of Crop Impaction

 

There are three common causes of crop Impaction. Palpation of the crop and X-rays are required to differentiate the exact cause.

 

• Foreign Material Crop Impaction
   

• Gizzard related Crop Impaction
   

• Contaminated Food Impaction

 

Foreign Material Crop Impaction

 

The swelling in the crop may be foreign material (e.g. string, rope, plastic, gladwrap, alfoil, paper, synthetic materials or any other fibrous material) eaten by the chicken that is unable to pass out of the crop because of its size or consistency.

A bird with this type of impaction will suddenly lose interest in food and twist its neck from side to side in an attempt to push food through the crop.

Barium meal X-rays are required to differentiate this type of foreign body crop impaction from gizzard related crop impactions.

Immediate surgical removal of the foreign impaction brings about an immediate and full recovery. Surgery is best performed before a life threatening crop infection (known as sour crop) occurs.

Often nutritional deficiencies either from inadequate roughage or diet and parasitic gastrointestinal infections are the underlying cause of the aberrant foraging behaviour that leads to this type of impaction. This form of crop impaction is prevented by removing hazardous material from the backyard and by adjusting the diet (see Poultry Health Programmes).

 

Gizzard Related Crop Impaction

 

More often crop impaction (identified as a hard ball-like swelling in the crop) is the result of problems lower down in the gastrointestinal tract that have created a gizzard malfunction. This is the most common cause of crop impaction.

Identifying the reason for the gizzard malfunction will reveal the underlying cause and best treatment for this type of crop impaction, which is common in backyard chickens.

Fluctuating weather conditions (e.g. sudden cold, wet or hot spells) are often involved with this type of crop impaction (i.e. due to a gizzard malfunction). The ingestion of contaminated food (decaying table scraps etc.) is another cause of this type of impaction.

Fluctuating weather conditions affect the metabolism of chickens and alter the ph levels within the crop, stomach gizzard and cloaca. The resulting increased alkalinity affects the normal passage of foodstuff through the gastrointestinal tract and predisposes it to electrolyte imbalances, infectious agents and gut irritability. These metabolic changes cause the chicken to search for mineral salts in an effort to counteract the electrolyte imbalance. Egg laying hens are most likely affected as they may develop mineral cravings following weather changes associated with gizzard and intestinal malfunction.

Afflicted chickens will also seek natural astringent substances such as clays and charcoals in an effort to relieve their discomfort. Unfortunately, in search of these substances they eat contaminated materials such as garden soils, potting mixes, shell grits, rocks, nails, screws wire and brick pieces etc. that are often extremely toxic with moulds, bacteria or heavy metals.

These contaminated items further upset the stomach and gizzard normal functions inciting them to eat more of these substances. This viscious cycle compounds the problems and results in serious gizzard and proventriculus impactions with associated toxic infections that is extremely life threatening.

With gizzard based crop impactions non-specific signs of illness (disinterest in food, inactivity and a pasted vent) usually appear before the swelling in the crop becomes obvious. Other Symptoms of Crop impaction described above follow.

X-rays are needed to diagnose gizzard related crop impaction and to predict the outlook with treatment. X-rays reveal the gizzard to be impacted with organic, mineral and soil materials that the bird has over-engorged upon in an effort to relieve the abdominal discomfort.

On X-rays, the presence of gas in the crop, proventriculus, intestines and cloaca are signs of life threatening complications with bacteria, yeasts and fungus indicating a full recovery may be compromised. Cultures are needed from crop and dropping samples to identify these germs and determine the best antibiotics to use.

The outlook for recovery is best when treatment is initiated at the first signs of illness and worst with long standing crop and gizzard impactions. Recovery is less likely when X-rays reveal gas and the presence of contaminated soil or other material impacted in the crop, proventriculus and gizzard.

A good outlook is predicted when there is a rapid response (within 5 minutes) to Emergency First Aid Treatment. A poor outlook is anticipated when there is no response to Emergency First Aid Treatment within 15 minutes.

 

Crop Impaction Due to Contaminated Food

 

Show and backyard chickens are often exposed to toxic moulds and bacteria found in contaminated pellets and grain, decaying table scraps, compost heaps, potting mixes, grass clippings, bark and plant mulches, pen bedding and wet areas beneath drinking water vessels and taps. Gizzard and crop impaction are sometimes a consequence of ingesting these toxins.

Fumonisins toxins produced by Fusarium moulds may cause proventriculus and gizzard malfunction, liver disease and bone abnormalities and occur as a result of feeding maize, wheat and other cereal grains that are contaminated with this mould. These moulds are most active during warm wet weather of autumn and winter. Ingestion of foods tainted with these toxins is often the underlying cause of gizzard blockages, egg peritonitis and egg laying problems in backyard chickens and show poultry.

 

Home Remedy for Crop Impactions

 

Start treatment in the morning by dropping a small amount of olive oil or liquid paraffin (2-3ml) into the bird's mouth and then gently massaging the crop to help break up the compaction and repeat this procedure in the afternoon. Feed a soft food such as layers mash and again add some natural yoghurt to soften the food and neutralise any bacterial build up in the crop.

 

Intensive Care Treatment

 

Veterinary attention is most successful when sick birds are presented before they have lost their appetite or shut their eyes in pain.

Immediate First Aid Treatment aims to restore energy, fluid levels and appetite. An attempt is made to relieve the impaction by flushing and emptying the crop with 20-30mls of heated saline solution if the bird is looking more alert following the initial first aid treatment, as the crop flushing is a stressful process that may induce heart failure and death in birds seriously affected by mould and bacterial toxins.

Repeat crop flushing immediately followed with crop feeding an energy food is repeated three times during the day. This process may need repeating for 2-3 days to unblock the crop and gizzard and reestablish normal bowel mobility. Heat, small seeds and antibiotics are also given during the recovery process.