Could cannibalism be 'perfectly natural'? This scientist thinks so

A snowy egret typically has three nestlings at a time. Two, which were doused with a healthy supply of hormones while they are still eggs inside their mother's body, grow to be large and aggressive. The third is small and meek. In a good year, when food is abundant, the larger chicks will toss the smaller one out of the nest. But if resources are scarce, and the chicks get hungry, they'll stab their sibling to death and eat it.