Placements of broiler flocks should be planned to ensure that differences in age and/or immune status of
donor parent flocks are as small as possible. This will minimize variation in final broiler live weights. One
donor flock age per house is ideal. If mixed flocks are unavoidable, keep similar parent flock ages together.
Avoid mixing chicks from parent flocks under 30 weeks of age with chicks from parent flocks over 40 weeks
of age.