Variability in preincubation embryo development in domestic fowl. 1. Effects of nest holding time and method of egg storage.

Embryos of eggs from Single Comb White Leghorn hens were analyzed to determine whether nest holding time and method of storage had a significant effect on postoviposition embryonic growth prior to incubation. Eggs were collected from 38- to 42-wk-old hens naturally inseminated and housed in floor pens. The experiment had a 2 x 2 factorial arrangement of treatments with two nest holding times and two storage methods. Eggs were collected within 1 h of oviposition, placed on cardboard egg flats, and stored unpacked (Treatment 1), or put on flats, and packed in 30-dozen egg cases (Treatment 2). Eggs in Treatments 3 and 4 were marked within 1 h of oviposition, but remained in the nest for 6 to 7 h. These eggs were separated into unpacked (Treatment 3), and packed (Treatment 4) groups. All eggs were stored at 13.8 C for 4 days. A total of 250 embryos were staged after storage for development using the Eyal-Giladi and Kochav classification. Least square means (LSM) for stage of development were: Treatment 1, 10.76; Treatment 2, 11.52; Treatment 3, 12.41; and Treatment 4, 12.36. For the main effects, nest holding time significantly affected stage of development (P = .0001), but storage method (P = .1140) and nest holding time by storage method interaction (P = .0730) did not. Comparison of LSM of Treatment 1 versus 3 (P = .0001), 2 versus 4 (P = .0152), and 1 versus 2 (P = .0214) were significant, but Treatment 3 versus 4 (P = .8595) was not.(ABSTRACT TRUNCATED AT 250 WORDS)