Cannibalism stems from aggressive behavior of chickens and turkeys that may begin by feather pecking by socially dominant birds. It may also involve vent pecking immediately after oviposition, or picking at skin on the head, comb, wattles, or toes. No single cause has been identified, but crowding, excessive light intensity, and nutritional imbalances are correlated with its occurrence. Additionally, in overweight pullets entering egg production or hens in production, mucosa will protrude from the vent during and after egg laying, and this red tissue attracts pecking. Other factors are insufficient feeder space, mineral and vitamin deficiencies, skin injuries, and failure to remove any dead birds daily. In addition to the loss of birds due to pecking trauma, cannibalism often leads to transmission of infectious diseases (eg, erysipelas) and botulism.
Control depends on correcting or reducing the above risk factors. Interventions include correcting an inadequate diet, replacing mash feed with pelleted feed, rearing birds on floor litter rather than slats, reducing light intensity, and providing perches as a refuge for targeted birds. Environmental enrichment such as hanging white or yellow strings may be beneficial. Trimming the sharp distal end (tip) of the upper beak will decrease skin trauma from pecking; this may be done at 1 day of age and repeated between 6 and 12 wk of age in maturing pullets or turkeys. The tip of the beak can also be treated by infrared heat on the day of hatching, which results in a shortened beak with minimal stress. Cauterization is required to provide hemostasis during beak trimming in older poultry.