Limiting the cost of rejects

Rejects cost the poultry industry more than £23m a year, so what can producers do to minimise their losses? Olivia Cooper finds out

Almost 9.4 million chicken are rejected in the UK every year, haemorrhaging money from producers’ pockets and increasing processors’ costs. In addition, following the introduction of the Broiler Welfare Directive, growers with high levels of rejects are likely to trigger a visit by Animal Health.

However, by understanding the reasons behind rejects, and taking action to prevent them, growers can not only reduce losses, but boost bird welfare and productivity.

At a recent workshop organised by Datapoul, part of the South West Healthy Livestock Initiative, vet Richard Turner said Meat Hygiene Service inspectors rejected just over 1% of birds each year – in itself, perhaps, a negligible amount. But when 850m birds are produced every year, it quickly tots up, taking the loss of poultrymeat sales to producers of more than £21m a year. Processors also incur losses on potential sales, as well as disposal costs of about £2.3m a year.

Most rejects are made on quality grounds, rather than human health risks, and processors employ specialist staff to monitor birds at set points in the processing chain, says Mr Turner.

Under the Broiler Welfare Directive there are nine points at which exceptionally high incidences of disease or mortality will trigger an alert to Animal Health. These are:

Cumulative Daily Mortality; Dead on Arrival (DOAs); Ascites and Oedema; Cellulitis and Dermatitis; Emaciation; Joint Lesions; Septicaemia and Respiratory Disease; Foot Pad Dermatitis; Total Rejections.

Cumulative Daily Mortality is recorded by the producer, but on arrival at the processing plant, an inspector will assess DOAs, birds with physical injury and runts.

The birds are shackled, stunned and bled before entering the plucking room – another inspection point on the line. Here, inspectors look for bruising, fractures, runts, Marek’s tumours on the skin, as well as pendulous crops, ascites, lesions and other apparent problems.

The birds’ feet are then removed and inspected for foot pad dermatitis. The carcasses are eviscerated and the internal organs checked alongside the bird. “The liver is the focus and is the main organ inspected in the very short time they have to do the job,” says Mr Turner. “Where there are issues with the organs, the carcass is removed from the line.”

Full gizzards and crops may split during evisceration, contaminating the carcass, so growers should withdraw feed prior to destocking and ensure none is left on the floor for the birds to eat.

In the packing station, birds are checked for wing damage, bruising, scratches, hock marks and breast blisters, among other evident problems. They are then chilled, cut up and packaged. “All records should be sent to the official vet, entered into a national database and sent on to the farmer,” says Mr Turner.

Causal factors

It is usually possible to identify the cause of problems and ascertain whether they are the farmer’s or processor’s responsibility. For example, bruises will be red to purple for the first 12 hours, then turn purple to green from 12 to 24 hours, mainly green up to 48 hours, and yellow from then until 72 hours after the damage, at which point they usually disappear. “When looking at bruising in a post-mortem you can assess whether there was a problem on farm, in transport or at the plant.”

Some problems should be picked up on farm, including runts, emaciated birds, pendulous crops and skin conditions.

“If you have a runt you should be getting rid of it – there is no point in continuing to feed it and send it to the processor. Emaciated birds should also be culled – but look for the root cause, which may be viral or enteric infections. Close monitoring of the flock will alert the farmer to any sub-optimal performance, which can be addressed promptly.”

Pendulous crops are often caused by yeast infection, so farmers should check their feed bins for problems.

“Five common causes of carcass rejection: Cellulitis, fevered carcasses, livers with lesions, bruising and foot pad dermatitis.”

Growers should also check birds regularly for foot pad dermatitis and breast blisters, and take action to improve litter quality where necessary. “Foot pad dermatitis is a big problem – in conventionally reared chickens average UK prevalence varies between 14.5% and 18.1%.” Farmers should score 100 birds on a scale of 0 for healthy feet to 2 for severe lesions – a total score of 120 or more indicates a serious problem and may trigger a visit by Animal Health.

Poor litter can also cause breast blisters, but some breeds are simply more prone to blisters and bruising due to sharp keel bones. “Thankfully, we don’t see breast blisters very often as farmers’ management is generally good; gentle handling of the birds, dry litter and preventing overcrowding are all important factors.”

Scratches can be more difficult to identify on farm, and are often caused by flighty birds or breeds with sharp claws. Scratches can often become infected, resulting in cellulitis – a relatively common cause for rejects, says Mr Turner. “Cellulitis is literally an inflammation of connective tissues; it typically occurs between skin and muscles and may be an incidental finding in a range of conditions.”

It is usually caused by E coli infection of minor skin wounds or chicks’ navals, and can spread quickly, resulting in high levels of rejects. “Very few signs are readily detectable prior to slaughter, but affected flocks tend to have poorer than average productivity and uniformity.”

Skin problems

If dead birds are left in the house, others walk on them, infecting their own feet and claws and leading to a greater chance of infection when scratching occurs, he adds. Symptoms include a nicotine coloured stain on the groin and pus under the skin. “If identified at thinning there may be time for antibacterial treatment. But careful flock management with a view to reducing toe wounds has the greatest impact; routine monitoring of skin damage at about 25 days of age is good practice.”

Another common skin problem, particularly in older and free-range birds, is Marek’s Disease, which causes tumours in the feather follicles as well as the internal organs. “You will clearly see tumours on the liver in older birds, as well as an enlarged spleen. You can vaccinate, but it costs 4-5p a bird, so may not be economically viable.”

Dermatitis is another skin condition, linked to wet litter and immuno-suppressive diseases like Gumboro. Wounds infected by clostridium or staphylococcus bacteria may develop into nectrotic dermatitis, causing gangrenous skin, cellulitis, swollen liver and spleen and sudden mortality.

“Try to avoid skin trauma and immuno-suppression, and ensure good hygiene and litter,” says Mr Turner. “Get dead birds out of the house so as not to spread disease, and be very wary of where you spread your litter as it may cause botulism in cattle and sheep.”

Secondary infection

Many poultry conditions are secondary to other infections, including joint lesions, whereby pathogens like E coli, staphylococcus and mycoplasma spread down to the limbs. Signs include lameness, poor growth and increased mortality – and can be prevented by early disease treatment.

Where infection gets into the blood stream, it causes septicaemia and fevered, red carcasses. This usually follows chronic respiratory disease associated with E coli, Infectious Bronchitis or Acute Respiratory Tracheitis. Fungal spores like aspergillus in litter, or poor air quality, may also be a trigger. “Symptoms include lethargic, sick birds, with poor feed conversion. If you do get problems, take fresh carcasses to your vet to post-mortem examination, and consider PCR tests for the next crop.”

Poor ventilation and respiratory infections can also cause ascites, which causes sudden death in rapidly developing birds, progressive weakness and abdominal distension. A post-mortem examination will reveal a fluid-filled abdomen and liver enlargement.

Inflammation and pus will also be seen in cases of pericarditis – affecting the heart; peritonitis – affecting the abdomen; and perihepatitis – affecting the liver. “The inflammation is mainly bacterial in origin, causing poor growth and sudden death. Prevention is by good hygiene and management.”

Bacteria also cause necrotic enteritis in the intestine and liver lesions, which are becoming an increasing problem, says Mr Turner. “If you see wet litter, it may well be due to clostridial bacteria, causing enteritis. You need to act very quickly to treat the sickness, as when the birds are sent to slaughter the long-term effects on the liver lead to rejection, which sometimes comes as a surprise.”

Although some levels of rejects are inevitable, preventative action and good practice can reduce rejections and save money, he adds. “If you get a lot of birds rejected on day one, go and see the plant on day two – it’s very interesting to see your own birds going through without their feathers on. And contact your vet to discuss the right course of action to minimise any disease problems.”