Quote: You should always have oyster shell or similar on hand unless you live in an area which has sharp rocks in the soil. Don't worry about crushing eggshells up small for them, they can break them into small enough pieces themselves before swallowing, and the stones and grit in their stomachs will grind the eggshells into powder anyway. A chick's first grits are generally pieces of its own eggshell, but adult birds need something more robust, able to keep macerating their intake of hard grains and fibrous vegetation for a prolonged period before dissolving or being eliminated.
Another thing is that hatchery stock from intensive production/commercial lines are notorious for having inherited strong behavioral faults including cannibalism, excessive aggression, neurotic habits, etc. It can take several generations to breed it out. Sometimes there is nothing you can do that will stop them wanting to engage in destructive behavior.
You can stop the behavior but they will breed it on, but if you prevent its expression for several generations, it should dissipate as it has then become a redundant "instinct" or environmental coping mechanism. In situations where they are mechanically fed and watered, and people only visit to remove corpses or vaccinate etc, cannibalism is often rife and in such an environment, cannibalism serves a purpose and is a survival instinct. But it is not an inherent instinct in all chickens. Many will starve to death rather than commit cannibalism. With others though it is their first reaction.
In these cases the perfect environment won't stop them from harming one another because it's just their mental blueprint for social behavior they are following. Just like hatchery chicks committing cannibalism under a week old; it's a mental, instinctual aberration to view their own kind as food, but we bred that into them, and we can breed it out again. I bred it out of my flock quicker by not breeding the worst examples of it, and not purchasing intensively farmed poultry after the first two batches I brought. They were not worth it, except as an educational experience.
I highly recommend you breed your own, or buy from breeders who keep their birds under more natural conditions and cull for antisocial behaviors. Best wishes.
