A guide to the Pathology and Inspection of Poultry

In the UK we eat over 25kg of poultry meat per person per year and over 850million broiler chickens are slaughtered to meet the demand

The health and welfare of these birds is protected by the veterinary surgeons who work in poultry research, disease surveillance and for the Meat Hygiene Service

This is a guide to the common pathological conditions encountered in the modern processing plant

H Thompson

R Irvine

D J Taylor

W Steele

A Perthshire poultry plant

The modern poultry plant handles 10 thousand birds per hour and does this efficiently, hygienically and with compassion

It is the duty of the Veterinary surgeon to make sure standards are maintained at all times

The five major stages from farm to fork

Stage 1 Ante mortem inspection -------- Dead on arrivals

Stage 2 Inspection after stunning, bleeding, scalding and defeathering

Stage 3 Inspection after evisceration ------ the carcase and internal organs

Stage 4 Packing portioning and labelling

Stage 5 Customer complaints

Stage 1. Ante mortem and dead on arrivals

The birds reach the plant on lorries from the farm

The live birds in their transport modules are inspected by the Official Veterinary surgeon (OV)

The module drawers are moved to the hanging on bay, where, in subdued lighting live birds are lifted and hung upside down on a

moving line

Crated chickens arrive at the plant and await transfer to the shackling point

Shackling is done in darkness save for a single UV light source to keep the birds calm

Dead on arrival, from the shackling point ( 3 birds from 3,500)

Approximately one bird in every thousand is dead on arrival

Small or deformed birds can be culled at stage 1

Pathology of dead on arrival

• Acute heart failure (heart is not pumping blood around the body)

• Congestive heart failure with ascites ( Water belly)• Pectoral myopathy

• Colibacillosis

• Trauma

Ascites (water-belly, congestive heart failure)

• Ascites occurs due to stress on the cardiopulmonary system, and is characterized by a build-up of fluid in the abdomen of the bird. 

•   Birds may also die without any obvious symptoms.  Birds that do not die from the disease are considered inedible.

• There are many factors thought to affect the development of ascites.  The disease is stimulated by rapid growth, cold temperatures during brooding, excess dietary salt levels and/or genetic factors. 

• Preventative measures include slowing early growth, ensuring a comfortable and consistent brooding temperature to prevent chilling, and checking water quality for sodium content.  It is also important to adequately ventilate the bird housing area, as dust and ammonia can damage lung tissue and may be a causative factor of ascites.

Congestive heart failure( water belly) swollen abdomen congested carcase

Waterbelly – fibrinous ascites and congestion

Heart failure – note the huge heart and liver

THE DEEP PECTORAL MYOPATHY (DPM), CALLED ALSO GREEN MUSCLE DISEASE OR OREGON DISEASE,

is observed in heavy meat types of turkeys or chickens. The disease occurs because of ischaemic necrosis due to inadequate blood supply of

variously sized deep pectoral muscle groups. The lesion is uni- or bilateral and is detected as a slaughterhouse finding. Affected muscles have an

unusual green colour.

Deep pectoral myopathy (Oregon disease)

• AVIAN COLIBACILLOSIS is considered to be one of the major bacterial disease in the poultry industry world-wide.

• Avian colibacillosis is an infectious disease of birds caused by Escherichia coli, which is considered as one of the principal causes of morbidity and mortality, associated with heavy economic losses to the poultry industry by its association with various disease conditions.

• Colibacillosis of poultry is characterized in its acute form by septicemia resulting in death and in its subacute form by peri-carditis, airsacculitis and peri-hepatitis.

Ecoli septicaemia – peritonitis and pericarditis

Ecoli infection – pericarditis, perihepatitis

Crating injuries (eg. broken wings, trapped head), a thing of the past in the modern plant due to better design of the bird crates.

Stage 2 inspection after stunning, bleeding scalding and defeathering

• The birds are stunned unconscious and bled by the automatic cutters

• There is a manual backup before the carcases of the dead birds are dipped into the scald tank to help loosen feathers

• Still in the shackles the feathers are removed by the mechanical plucking machines

• The carcases are now ready for first visual inspection

Shackled live birds enter the stunner

Birds enter the stunner

Stunned birds

Stunned birds enter the neck cutter

Bleeding trough – an operator checks the birds to confirm all have been stunned and bled properly

The birds enter the scalder

The de-feathering machine

Out of the de-feathering machine

The first inspection point on the line

Rejected birds at first inspection point

Stage 2. Pathological findings

• Production faults - Welfare• Inadequate bleeding (redneck) • Poor defeathering • Bruises and fractures• Overscald• Mechanical damage• Contamination

• Disease findings• Waterbelly• Emaciation• Dermatitis ( breast blisters, ruptured air sacs plantar pododermatitis• Anaemia and jaundice

Redneck

Poor defeathering

Trauma and bruising

• Leg bone fractures can occur spontaneously on the farm during catching, transportation or shackling

• They are usually closed oblique fractures of the femur and the timing of the injury can be judged from the colour of the bruising

• Red within 24 hours, dark red, yellow or green 48-72 hours

• Rupture of the gastronemius tendon which can be unilateral or bilateral can also occur spontaneously

• With older lesions the green discolouration in the subcutaneous tissue close to the hock is distinctive

Oblique fracture of the femur

Trauma

Broken wing

Trauma

Freshly fractured femurFresh carcase bruising

Bruising of a few days duration

Ruptured gastronemius

Shackling damage

Overscald

Overscald

Machinery damage – no bleeding or haemorrhage

Fractured tibia/fibula

Skin tear by machinery

Faecal contamination

Water belly

Water belly with congestion

Emaciation (abnormal thinness caused by lack of nutrition or by disease) and congestion ( an excessive or

abnormal accumulation of blood or other fluid in a body part or blood vessel)

Breast blister(enlarged, discolored area on the breast or keel bone often seen in heavy birds)

COLIFORM CELLULITIS Is a bacterial disease causing chickens to develop plaques in their skin. It is caused by Escherichia coli. Chickens with skin trauma, especially scratches, have poor feathering and/or in crowded conditions are more predisposed to coliform cellulitis.

See more at: http://www.poultrydvm.com/condition/poultry-coliform-cellulitis

Coliform cellulitis

Coliform cellulitis

Contact dermatitis

• Several forms of contact dermatitis are recognised including plantar pododermatitis, hock burn, breast burn or scabby hip

• The common link is poor litter management.• The lesions start as ulcers or abrasions on the affected

part which become filled with black scabs of necrotic debris, bacteria and plant material.

Hock burn

Contact dermatitis

Hock burn

Contact dermatitis

Contact dermatitis

Pododermatitis

Contact dermatitis

Plantar pododermatitis – minor and severe stages

Contact dermatitis

Head pecking – with subsequent infection and ulceration

Dehydration and anaemia

Jaundice alongside an overscald for comparison

Stage 3: Inspection after evisceration

• The head is removed• An eviscerating machine removes the intestine

and internal organs• The carcase and viscera of each bird are

examined• Suspect or diseased organs and carcases are

rejected

The eviscerator from the PIA platform

Carcase and offal correlation

Stage 3: Inspection after evisceration

• Production faults• Mutilated carcases

• Disease findings• Water belly• Colibacillosis : perihepatitis, pericarditis• Hepatitis• Coccidiosis• Congenital defects

Mutilated carcase - skin torn by eviscerator

Ascites

Ascites

E coli septicaemia

Osteomyelitis following E coli infection ( characterized by a firm bony swelling (arrow) at the caudal thoracic vertebrae in a broiler)

Peri-hepatitis

Pericarditis

Pericarditis

Hepatitis

Coccidia

Bloody content in caecum

Coliform cellulitis

Congenital abnormality – defective keel bone (keel bone is an extension of the sternum (breastbone) which runs axially along the midline of the sternum

and extends outward, perpendicular to the plane of the ribs)

Congenital defect – defective abdominal skin

Wings are checked before proceeding to grading

Carcases enter the grading and cutting plant

Carcase grading

Stage 4: Packing, portioning and labelling

• The carcases are washed in potable water • Chilled down to 4 degrees C by cold air and

water jets • After a period of maturation, usually 8-10 hours

they are ready for bagging as oven ready birds or portioning and packing into plastic trays for supermarket chiller cabinets

The skill of the processor is to maximise the value of the product

Most products are now carefully labelled

Always look for the health stamp which denotes country of origin and the abattoir

Stage 5: Customer complaints

• Nothing is perfect ! Even with the best checks and controls customers will find faults when handling or cooking the finished product

• Complaints are usually directed to the Environmental Health Agencies

• A veterinary pathologist is sometimes required to identify the fault

Stage 5: customer complaints

• Customers are sometimes alarmed by unfamiliar pieces of normal tissue eg. Kidney or bursa of Fabricius

• Diseased or discoloured pieces of chicken as a result of disease may reach the consumer despite the best controls eg. Pectoral myopathy or breast blisters

Bursa Fabricius

Kidneys

Purchasers complaint

Spiced kidney

Normal fresh bird kidney

XN 2875

Abscess in breast muscle

A portion of chicken tikka

XN 2875

Inspissated pus from shelled out abscess

Breast blister from broiler chicken

XN 3160

Raw chicken as presented

Fixed piece of same chicken showing distinctive green colour of pectoral myopathy

A customer returns a piece of fresh

discoloured chicken from a supermarket

XN 3160 Deep pectoral myopathy in the chicken, “Oregon disease”.