What causea cannibalism?
Cannibalism often starts as feather pulling or picking while the birds are only a few weeks old, or as investigative pecking at any age. These behaviours can escalate to aggressive pecking, particularly if injury occurs. Scientific study has shown that any stressor (or combination of stressors) can trigger this behaviour and can lead to serious aggressive pecking and cannibalism.
These stressors include crowding, bright light intensity, high room temperature, poor ventilation, high humidity, low salt, trace nutrient deficiency, insufficient feeding or drinking space, nervous and excitable birds (hereditary), external parasites, access to sick or injured birds, strss from moving, boredom and idleness, housing birds of different appearance together and birds prolapsing during egg-laying.
Prevention and treatment of cannibalism
As cannibalism can become a learned behaviour it can be difficult to treat once it has started in a flock. Therefore preventiom should be the main aim and as such, good husbandry practices should aim to minimise the stressors listed above as potential cause for cannibalism. Some strains of birds have been shown to have a higher tendency towards developing aggressive pecling behaviour and therefore strains that are more placid should be preferred.
The broad range of factors that can trigger cannibalism can makw it very difficult for management to controll all of these factors for the entire life of the flock. Bright light is a known factor that leads to cannibalism but control of lighting levels in some poultry housing systems can be very difficult, if not impossible (such as in free range systems).
Where outbreaks of cannibalism have occurred in a flock, or where there is a reasonable concern that management strategies cannot be guaranteed to prevent an outbreak, then beak trimming of the birds nay be used as a control measure.
Trimming of the aharp tip of the upper, and sometimes alao lower, beak reduces the damage that is caused by aggressive pecking. Further information on the practice of beak trimming can ve found in the section on Beak Trimming.
The spread of the behaviour may be able to be controlled if the injured and aggressive birds can be rapidly identified and removed from the flock. Provision of escape areas may also help in floor-housed flocks. Other control methods that have control methods that have been tested include the use of spectacles to prevent foward vision, bits that beak and coloured contact lense to prevent the identification of blood on another bird.
There is evidence that cannibalism may be alleviated through the use of high fibre diets. It is believed that high fibre diets enhance gut development and gizzard function, which in turn help reduce aggressive behaviour in hens.
It is important for a farmer to provide birds with a well-balanced diet and an ample supply of water, this is because cannibalism has been linked to deficiencies in protein, sodium and phosphorus.
Mixing of different types, sizes, and colors of fowl
Mixing different ages and sizes of birds with different traits promote pecking by disrupting the flock’s normal pecking order. Never brood different species of fowl together in the same pen. Don’t brood feathered leg fowl, crested fowl or bearded birds with ones without these traits. Curiosity can also start pecking. Toe pecking in the first few weeks is often started due to curiosity of the different colors or traits.
Take extra precautions with slow feathering birds. Most cannibalism occurs during father growth in young fowl. Birds with slow feathering have immature tender feathers exposed for longer periods of time leaving them open to damage from pecking. Don’t raise slow feathering birds with other fowl.
Anytime you add or remove birds from a flock you disrupt the pecking order of the flock. It is best to introduce any new birds into your pen by splitting the pen with a wire walk for atleast a week to help the birds to get to know each other. Also, adding the birds to the perch at night can help.
Always supervise new introductions to the flock and intervene if the pecking gets out of control and birds are getting hurt. It may take a week or more for flock to re-establish the new pecking order.