Allow the birds to use up their energy in an enclosed outside run. This will keep the birds busy and allow them to peck greens, ground and insects instead of other birds.
Give the birds a large handful of fresh greens like clover grass or weeds, each day. This increases the fiber in the birds’ diet. A high fiber diet will keep the birds’ gizzard full and keeps the birds more content. Small parts of baled green leafy hay will also give the birds something to pick at.
Use of mechanical devices like plastic peepers or blinders in aggressive birds is advisable.
Placing colored or shiny items for the birds to pick at and occupy their time can draw attention away from other birds. Hanging shine cans just above eye level can serve as a toy.
Finally, beak trimming is used in problem flocks. Trim the beak by removing about 1/3 of the tip of the beak providing a square tip. This makes it difficult for the birds to harm each other. However, beak trimming should be done by someone experienced in proper trimming.
Treatment for Cannibalism Outbreak
Since cannibalism can be caused by several conditions, you may not be able to determine the exact cause of the problem. However, stress no matter how slight, is usually the main factor.
Try to correct any practices which may have lead to cannibalism.
Darkening the facilities by using red bulbs.
Remove any badly injured birds.
Applying an anti-peck ointment on any damaged birds usually stops pecking. Lower the pen temperature a bit if possible