... selected lines. In a study of inbreeding depression on pro-duction traits of White Leghorns [34], inbreeding tended to reduce egg numberand delayed the age at first egg in all lines, but in a line ... nobird, of each homozygous genotype at the NA locus.2.2.3. Coefficient of inbreeding In the first generation, the coefficient of inbreeding was assumed to be 0,then individual inbreeding coefficients ... analyzed by increasing thenumber of generations successively taken into account in nine different subsets of the whole data set. Pedigree information back to generation 0 was included in the analysis...