DURATION OF INCUBATION AND EFFECT OF EGG STORAGE ON HATCHING RATE IN LINES SELECTED ON RESIDUAL FEED CONSUMPTION

Duration of incubation and effect of egg storage on hatching rate in lines selected on residual feed consumption. Two lines of laying hens submitted to a divergent selection for residual feed intake (R+ with high feed intake, R- with low feed intake) had previously shown differences for fertility and hatching mte to the advantage of R-. In the present work these lines have been compared for the duration of incubation (in 1987 and 1988), then for their response to the time during which eggs were kept before setting for incubation (in 1990). The duration of incubation was longer for the R+ line than for R-by almost-equal-to 9.5 h and 8 h in 1987 and 1988 respectively. In 1990 on the whole, a highly significant disadvantage was found for the R+ line in hatchability, as well as a depressing effect of a longer storage of the eggs on hatchability. There was no significant line x storage duration interaction. However, the data suggest a some what different distribution of the causes of loss at hatching in the 2 lines, possibly influenced by the duration of egg storage.