Hematocrit as An Indicator of Egg Production in Turkey Breeder Hens

Weekly hematocrit measurements were correlated with weekly egg production throughout the breeding season of Large White turkey hens. A highly significant negative regression of egg production associated with hematocrit was observed, occurring without regard to differences in the incidence of broodiness in the flocks under study. Approximately 20% of the total variance in egg production was accounted for by the regression on hematocrit. A high hematocrit (≥45%) was a fairly accurate indicator of poor production; however, not all hens which laid poorly (≤33% production) during a weekly period exhibited a high hematocrit. Virtually all hens having a hematocrit of 48% or greater were totally out of production during the weekly period surrounding the hematocrit measurement. The hematocrit may be a useful method for rapid identification of a significant proportion of the unproductive hens in a turkey breeder flock. Elimination of environmental temperature extremes may enhance the usefulness of this technique.