Botulism (Limberneck) in Laying Hen ...

Botulism (Limberneck) in Laying Hens

Botulism (Limberneck) in Laying Hens

Happenings / Clinical Signs

Visibly sick birds

  • Few  visibly sick birds
  • Birds appear comatose and may seem dead
  • Affected birds are found sitting and are reluctant to move
  • Limberneck, the original and common name for botulism, precisely describes the paralysis of the neck
  • Birds acting listless, lethargic and depressed


  • Low mortality or increases gradually
  • Mortality is related to the amount of acquired toxin.
  • Mortality up to 8 %  in two weeks period has been observed

Dead Birds

  • Birds are usually in good condition 
  • With low toxin doses the birds may  dies in poor body fleshing condition due to paralysis


  • Hens had closed eyes (eyelid  paralysis)

Neck wings breast abdomen shanks legs hocks feet joints vent skin

  • Flacid paralysis of the neck, wings, and legs


  • Flaccid paralysis of legs, wings, neck and eyelids

Lameness or unusual movement incoordination ataxia

  • If coaxed to walk, they appear lame


  • Ruffled feathers, which may fall out with handling

Clinical disease in chickens whose predominant features are flaccid paralysis of legs, wings, neck and eyelids. Limberneck, the original and common name for botulism, precisely describes the paralysis of the neck. Death result from cardiac and respiratory failure. Affected chickens have ruffled feathers, which may fall out with handled. Morbidity (percentage of sick birds) and mortality are related to the amount of acquired toxin.

Causing Agents
Toxic. Caused by a bacterial toxins produced by Clostridium botulinum mainly types A/C.
Affected Systems/Organs
Neurological and Locomotor System. Neck, Wings and Legs.
The toxin is produced in decaying animals (usually carcasses) and plant waist and toxin-containing material (Pond-mod, carcasses, maggots) is consumed by the birds.
Mainly Affects
Removal all dead birds on daily basis. Avoid access to toxin. Many sick birds, if isolated and provided with water and feed, will recover.
Suggested Actions
  • Can be confirmed with clinical signs and gross lesions
  • Can be dealt with in house
  • Diagnosis should be confirmed with rapid assays and/or a certified laboratory
  • Veterinary intervention is recommended

Impact on Egg quality


Impact on Liveability


Impact on Production


Overall Economic Impact


Y.M. Saif.2008.Disease of Poultry. 12th Edition. page 881

David E. Swayne. 2013. Diseases of Poultry 13th Edition. page 46

Raymond W. Sweeney 2016. Outbreak of Type C Botulism in Commercial Layer Chickens. Avian Disease 60(1): 90-94

Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition.


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