Relationship of Late Embryo Loss and Anomalies in Broiler Offspring

A previous study of Mississippi broiler complexes indicated a significant increase (0.640 to 1.77%) of embryonic total gross anatomical anomalies (TA) in the hatch residue. A separate field study in a single broiler complex of 8 breeder flocks, each hatching in 2 machines on the same day, illustrated a positive correlation between TA and total late stage embryo loss (TLEL; 16 to 21 d of incubation). The current study examined egg hatch residue from 92 selected breeder flocks that were hatched in each of 2 machines on the same date, with each respective machine being identified during egg residue analysis as having either low or high TLEL. Five makes of multistage incubational units were utilized within 10 different hatcheries in 7 states. The eggs were from breeders that comprised 32 weekly age groups (wk 27 to 61) and 5 separate strain crosses. When the egg residue results from the 92 flocks (hatching in 184 machines) were placed into 1 of 2 groups according to level (low and high) of TLEL, the high TLEL group showed a significantly lower estimated hatching efficiency (EHF) and significantly higher levels of TA and embryo head misorientations toward the small end of the egg than did the low TLEL group. The percentage change in EHF was 1.28% between eggs belonging to low (93.8%) and high (92.6%) TLEL groups. Also, TLEL in both low and high groups was significantly (P ≤ 0.0001) correlated with EHF, TA, total cracked or crushed eggs, and with eggs having embryo heads misoriented toward the small end. These results strongly suggest that TA plays a minor role, if at all, as a cause of lower EHF and that TA incidence may serve as a biomarker for hatching efficiency.