This may be caused by two factors, mostly combined together:
1. Inadequate nutrition - especially a lack of protein or vitamins. As the supply of these nutrients will not be adequate even with sufficient amounts of grain, sources of protein need to be added.
2. Breeding in a limited space with insufficient opportunities for hens' natural activities, such as scratching, gathering food on the ground or on plants or dust bathing. If this is possible in view of the local conditions, providing a better living environment to hens, especially a larger space with more stimuli for the animals, is advisable.
Feeding chickens should follow several scientifically proven principles, as the composition of the daily feeding dose changes in many different nutrients throughout various stages of life or production. Therefore, complete fodder provides a range of nutrients in a balanced composition and cannibalism should be minimized when using this fodder.
If this phenomenon occurs especially with traditional feeding, the feeding dose must be supplemented with animal protein, such as curd cheese or meat leftovers. Meat cans for dogs have lately been a popular available supplement. Alternatively, any of the available vitamin supplements is suitable.