is not so much that there has been one breeding goal for
meat-producing juveniles and another for egg-producing
adults, as that, until recently, very little attention has been
paid to the welfare of the adults at all.
Broiler breeders have
been the by-product of selection for fast juvenile growth
rate. The consequent need for feed restriction in the parents
could also be mitigated by selecting for slower growth rate
in broilers but as we have seen, this conflicts with efficient
production.