As farmers gain experience with cage-free flocks, their longevity increases, new research reports.
The study, authored by Dr. Cynthia Schuck-Paim and others, included data from 16 countries, 6,040 commercial flocks, and 176 million hens in a variety of caged and cage-free systems.
Mortality rates were compared between conventional battery cages and large cages with perches, nests and litter.
She said the lower mortality rates are not necessarily a good indicator of health or welfare. And she said mortality rates were originally no better than in caged housing, but improved as managers gained experience.
“What makes animals suffer is not necessarily what kills them,” she said.
“Unhealthy individuals can suffer for extensive periods in caged conditions before succumbing to their fate, if they die at all; whereas other deaths, for example accidents or predation, may affect otherwise healthy individuals.”