INFLUENCE OF EGG SEQUENCE POSITION ON FER TILITY, HATCHABILITY AND EARLY EMBRYONIC MORTALITY

Studies with turkeys (BACON and NESTOR, 1979), White Leghorn (BUHR, 19 90), and broiler breeders (ROBINSON et al., 1991) have shown that firs t eggs in a clutch tend to have lower fertility and hatchability than subsequent eggs. This study was undertaken to examine the influence of egg sequence position on fertility, hatchability and early embryonic mortality in two brown egg type female lines. Hatching eggs were colle cted daily from 1170 hens, beginning in 4-week-period 10, i.e. at appr oximately 60 weeks of age. Hens were individually caged and artificial ly inseminated once per week with pooled semen from a common male line . Egg sequence position was determined from production records. In two settings 14314 eggs were set. Of these, 13.2% were first eggs after a one-days-pause, 1.5% first eggs after a longer pause, 11.6% second, 5 8.2% middle and 12.4% last eggs, 3.1% were single eggs. To determine t rue fertility, clear eggs were broken after candling on the 8th day of incubation. Differences between the positions were significant for al l traits except for early embryonic mortality in line D4. Fertility wa s higher (ca. 2%) in second compared to first eggs in both lines. Hatc hability in first eggs declined by 8-9% and 5-6% in line C6 and D4, re spectively, compared to middle eggs. Early embryonic mortality was sig nificantly higher in first eggs in line C6 by 3%.