Table 3.

Variance components for the environmental variance (exponential model) of eggshell color in purebred and crossbred laying hens

Variance component	Purebred	Crossbred
Sire	0.019 (0.003)	0.017 (0.005)
Permanent environment	0.32 (0.006)
Cage		0.098 (0.010)
Residuala	1.847 (0.007)	5.786 (0.030)
Genetic	0.077 (0.011)	0.067 (0.020)
$h_v^2$ b	0.010 (0.001)	0.011 (0.003)
GCV bVe	0.277 (0.019)	0.259 (0.039)

Standard errors are provided between brackets

^aThe residual variance for purebreds is lower than in crossbreds due to sire model adjustment in crossbreds

^bApproximate standard errors were calculated according to formulae in the “Appendix”