Table 2.

Variance components and heritability (standard error) of the crossbred Thai indigenous chickens.

Chickens	KKU1					KKU2
Traits	SCA	${\mathit{\sigma }}_{\mathit{a}}^2$	${\mathit{\sigma }}_{\mathit{e}}^2$	${\mathit{\sigma }}_{\mathit{p}}^2$	${\mathit{h}}^2$	SCA	${\mathit{\sigma }}_{\mathit{a}}^2$	${\mathit{\sigma }}_{\mathit{e}}^2$	${\mathit{\sigma }}_{\mathit{p}}^2$	${\mathit{h}}^2$
BW0	0.21	9.58	4.73	14.31	0.669 (0.05)	0.07	8.93	5.15	14.08	0.634 (0.04)
BW2	10.61	457.73	554.62	1012.35	0.452 (0.07)	8.08	249.05	384.98	634.03	0.393 (0.05)
BW4	32.10	2698.20	4506.30	7204.50	0.375 (0.05)	25.26	1924.00	3835.00	5759.00	0.334 (0.03)
BW6	38.65	4094.80	7581.30	11,676.10	0.351 (0.02)	32.85	3500.50	6925.00	10,425.50	0.336 (0.04)
BrC6	0.37	1.33	3.04	4.37	0.304 (0.03)	0.30	1.07	2.78	3.85	0.278 (0.03)
ADG0–2	0.75	2.12	3.30	5.42	0.391 (0.02)	0.58	1.13	1.98	3.11	0.362 (0.02)
ADG0–4	1.14	3.67	7.64	11.31	0.324 (0.02)	0.90	3.17	7.12	10.29	0.308 (0.02)
ADG0–6	1.43	5.85	15.34	21.19	0.276 (0.01)	1.05	4.77	15.77	20.54	0.232 (0.01)

SCA = specific combining ability; ${\sigma }_a^2$, ${\sigma }_e^2$, and ${\sigma }_p^2$ = additive genetic variances, residual variances, and phenotypic variances, respectively; $h^2$ = heritability; BW0 = birth weight (g); BW2, BW4, and BW6 = body weight at 2, 4, and 6 weeks of age (g), respectively; BrC6 = breast circumference at 6 weeks of age (cm); ADG0–2, ADG0–4, and ADG0–6 = average daily gain at 0–2, 0–4, and 0–6 weeks of age (g/day), respectively; KKU1 = crossbred chicken between commercial broiler and Thai indigenous synthetic chickens (Kaimook e-san1); KKU2 = crossbred chicken between Kaimook e-san2 and Kaimook e-san1 (both of which are Thai indigenous synthetic chickens).