Relationship of Embryo Weight as a Percent of Egg Weight to Efficiency of Feed Utilization in the Hatched Chick

The relationship between efficiency of embryonic utilization and efficiency of utilization of feed by the hatched chick was studied by comparing the 10-day embryo weight as a percentage of egg weight (percent embryo weight) to feed conversion ratio of their full-sibs from 1–9 weeks of age. There was no relationship between embryonic efficiency (as measured by percent 10-day embryo weight) and early (1–5 week) chick efficiency (as measured by feed conversion ratio). The correlations of .19 and .12 obtained for percent 10-day embryo weight and 5–7, 7–9 feed conversion also indicated a lack of relationship between embryo efficiency and latter chick efficiency. Similar low correlations between percent 10-day embryo weight and feed conversion (.12 and .16) and embryo weight with growth weight (0 and −.06) were obtained. A negative correlation of −.46 between percent embryo weight and egg weight resulted because of the rather constant embryo weight over varying egg weights.