An investigation on commercial farms of factors thought to contribute to egg cracking

Synopsis An investigation of 52 egg production units showed that in battery units, but not under other systems of husbandry, the proportion of defective eggs produced by birds in their second year was more than twice that of the first year. The proportion of defective eggs was unrelated to the shell thickness (measured by the deformation test on random samples of sound eggs from the same flocks). Damage to eggs during collection and packing was trivial, relative to the proportions of defective eggs found in the nests or cages.