Cannibalism, Vent Pecking, Peckout, Prolapsed Cloaca in Laying Hens
Vent pecking generally occurs immediately after oviposition, and exposure of the mucus membrane stimulates pecking by others birds.
It is more common when birds in floor systems lay their eggs on the floor in crowed areas
Vent pecking is responsible for at least 80% of all prolapses. It has been hypothesized that vent pecking may be the initiating lesion that triggers the onset of salpingitis in the oviduct and perhaps egg peritonitis
Cannibalism involves ingestion of part of other conspecifics, including skin, tissues and organs
Vent pecking occurs as egg laying begins, but other instances starts at peak production or after and continuing throughout all the laying period
Feather pecking and cannibalism tend to reoccur and it is suggested that it may be a learned behaviour
Happenings / Clinical Signs
Visibly sick birds
- Few visibly sick birds
- Wounds around the vent
- Appearance of blood on exposed mucus membrane of the vent
- Birds with blood on their beaks will be seen
- Increase flock mobility or activity
- Vent pecking frequently occurs immediately after an egg has been laid when the cloaca often remains partly everted exposing the mucosa
- Vent pecking occurs as egg laying begins, but other instances starts at peak production or after and continuing throughout all the laying period
- Feather pecking and cannibalism tend to reoccur and it is suggested that it may be a learned behaviour
- Today, cannibalism is more common in the modern brown hybrids than the white layer lines
- Up to 30% of the flock may be affected during an outbreak
- The type of housing system markedly affects the prevalence of vent pecking with 22.5% of hens affected in free-range systems, 10.0% in barn systems, 6.2% in conventional cages and 1.6% in furnished cages, with a similar rank for the severity of vent pecking injuries
- Low mortality or increases gradually
- Cumulative mortality may be high
- Good body fleshing condition or Well-fleshed
Body Parts (Neck wings breast abdomen shanks legs hocks feet joints vent skin)
- Pecking damage to the cloaca the surrounding skin and underlying tissue
- Carcasses are found without viscera and with wounds around the vent (possible evisceration)
- Bloodstained feathers around the vent
- Blood stained or smears on eggshells
- There are often a lot of bloodstained eggs seen in flocks
- Bloodstained feathers around the vent
This is a behaviour expressed by dominant birds at subordinates.
Vent pecking is more common when birds in floor systems lay their eggs on the floor in crowded areas or nest colony system. It occurs immediately after ovoposition, and exposure of the mucous membrane stimulates pecking by other birds.
Apperance of blood on exposed mucous membrane may lead to the death of the bird due to cannibalistic behaviour from the other birds in the flock or the bird has to be culled due to the severity of the injuries.Vent pecking occurs as egg laying begins, but other instances starts 35 weeks old.
The number of blood stained or smears on eggshells increased. Some hens have bloodstained feathers around the vent due to the severe injury of mucous membrane of the vent.
- Causing Agents
- A complex multi-factorial behavioural problem. Predisposing factors include overcrowding, excessive light intensity or variation in environment (e.g. through shafts of light in the house or shed, high temperature, nutritional deficiencies, feed form, boredom, and strain of bird). Adequate husbandry. Rule out the factors such as: colony size, stocking density, nutrition and light regimen. In free-range and barn laying flocks, where pecking can be more of a problem, it is standard practice to use 0.18-0.20% sodium in the ration while for cage birds .014% is adequate. The higher level does not prevent pecking completely but it reduce the susceptibility of the flock to developing the vice, which is usually triggered by management factors.
- Affected Systems/Organs
- Integumentary system; Vent and Skin
- Mainly Affects
- Adequate husbandry. Rule out the factors such as: colony size, stocking density, nutrition and light regimen
- Suggested Actions
- Can be confirmed with clinical signs and gross lesions
- Can be dealt with in house
- Technical assistance recommended
- Can be managed with feed additives, off-the-shelf medications
- 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 1149
David E. Swayne. 2013. Diseases of Poultry 13th Edition. page 1233
Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition. page 97, 545
Steven Leeson, John D. Summers. 2008. Commercial Poultry Nutrition. Third Edition.
Donald D. Bell, Williams D. Weaver. 2009. Commercial Chicken Meat and Egg Production. Fifth Edition.