Table 6. Comparison of egg quality between crossbred Korean native chickens and Hy-Line Brown from 24 to 64 weeks after hatching¹

Period	Treatments²													SEM³	P-value
Period	CFCK	CFYC	CFYD	CKCF	CKYC	CKYD	YCCF	YCCK	YCYD	YDCF	YDCK	YDYC	Hy-Line brown	SEM³	P-value
Egg weight (g)
Week 24	51.19^a	52.86^ab	53.98^ab	52.96^ab	51.34^a	51.34^a	54.89^ab	54.99^ab	54.53^ab	53.34^ab	57.38^b	56.76^b	53.67^ab	0.275	< 0.001
Week 28	53.91^abc	51.72^a	52.59^ab	60.54^d	54.11^abc	52.67^ab	56.10^c	54.04^abc	54.72^abc	54.21^abc	55.31^bc	52.06^ab	61.03^d	0.189	< 0.001
Week 32	55.71^a	56.06^a	56.01^a	63.99^b	55.77^a	56.23^a	59.15^ab	58.09^ab	56.31^a	59.72^ab	57.66^ab	55.63^a	64.33^b	0.384	< 0.001
Week 36	55.94^a	58.27^abc	59.97^bc	57.40^ab	55.93^a	55.30^a	57.59^ab	55.24^a	61.26^cd	58.39^abc	56.31^a	58.47^abc	63.56^d	0.187	< 0.001
Week 40	57.25^abc	56.59^abc	59.2^abc	66.20^de	60.15^bc	57.87^abc	61.78^cd	57.72^abc	55.47^ab	57.95^abc	55.84^ab	53.78^a	67.63^e	0.332	< 0.001
Week 44	55.73^b	56.75^b	57.01^b	63.17^cd	58.32^bc	57.62^bc	58.31^bc	55.09^ab	55.66^b	58.26^bc	54.57^ab	49.53^a	64.38^d	0.334	< 0.001
Week 48	57.44^abc	59.82^cd	58.40^bc	57.88^abc	55.91^ab	57.82^abc	58.53^bc	57.19^abc	62.10^de	55.04^a	58.64^bc	59.41^cd	64.18^e	0.177	< 0.001
Week 52	57.53^a	57.02^a	57.79^a	62.33^ab	57.08^a	60.67^ab	59.36^ab	58.02^a	57.70^a	56.96^a	56.79^a	55.70^a	65.00^b	0.388	0.001
Week 56	57.90^abc	56.74^ab	54.61^ab	59.44^bc	55.07^ab	54.69^ab	57.78^abc	54.84^ab	54.02^ab	53.96^ab	53.21^a	53.60^ab	63.43^c	0.337	< 0.001
Week 60	60.03	55.9	57.83	61.56	56.8	71.06	58.3	59.36	57.2	55.43	55.33	54.26	64.17	1.354	0.582
Week 64	59.15^ab	62.88^bc	59.8^ab	52.59^a	53.51^a	58.03^ab	58.75^ab	59.29^ab	68.54^c	51.82^a	62.73^bc	69.30^c	63.98^bc	0.493	< 0.001
Week 24–28	52.55^ab	52.29^ab	53.29^abc	56.76^de	52.73^ab	52.01^a	55.5^cde	54.52^abcd	54.63^bcd	53.78^abc	56.35^de	54.41^abcd	57.36^e	0.144	< 0.001
Week 32–64	57.41^ab	57.78^ab	57.85^ab	60.51^bc	56.51^ab	58.81^ab	58.84^ab	57.21^ab	58.70^ab	56.40^a	56.79^ab	56.63^ab	64.52^c	0.232	< 0.001
Week 24–64	56.53^ab	56.79^ab	57.02^ab	59.83^bc	55.82^a	57.58^ab	58.24^ab	56.72^ab	57.96^ab	55.92^a	56.71^ab	56.23^a	63.22^c	0.195	< 0.001
Eggshell color
Week 24	37.17^b	52.83^f	48.63^def	41.93^bc	47.73^def	46.27^cde	48.63^def	51.40^ef	47.17^de	47.57^de	48.63^def	43.57^cd	25.83^a	0.295	< 0.001
Week 28	54.70^e	54.00^e	49.70^de	54.37^e	52.57^de	51.33^de	49.13^de	54.77^e	39.93^b	46.47^cd	49.70^de	41.73^bc	23.23^a	0.361	< 0.001
Week 32	52.77^bc	51.53^bc	47.83^abc	50.83^bc	46.53^abc	49.40^bc	47.37^abc	52.13^bc	36.53^ab	43.63^abc	62.37^c	37.6^abc	23.50^a	0.374	0.001
Week 36	34.07^b	45.23^d	45.93^d	36.27^bc	49.60^d	40.97^bcd	42.90^bcd	46.00^d	43.53^cd	44.87^cd	44.20^cd	44.43^cd	23.57^a	0.51	< 0.001
Week 40	41.40^cd	44.50^cde	43.27^cde	48.70^e	44.67^cde	46.53^de	45.00^de	47.40^de	34.10^b	42.63^cde	44.73^cde	38.50^bc	22.30^a	0.369	< 0.001
Week 44	41.73^cde	41.67^cde	42.10^cde	48.17^e	44.37^de	40.70^bcd	42.03^cde	45.23^de	34.20^b	42.03^cde	44.37^de	36.17^bc	22.63^a	0.403	< 0.001
Week 48	32.17^b	42.60^c	40.60^c	36.73^bc	36.37^bc	40.23^c	38.70^bc	42.90^c	37.53^bc	37.60^bc	36.47^bc	37.47^bc	22.40^a	0.452	< 0.001
Week 52	41.70^bcd	44.53^cd	44.87^d	44.30^cd	42.67^bcd	44.77^d	41.97^bcd	45.10^d	36.90^b	42.13^bcd	46.70^d	37.33^bc	22.00^a	0.414	< 0.001
Week 56	36.37^bcd	33.40^bc	37.93^bcd	35.70^bcd	39.70^d	38.30^cd	38.20^bcd	38.73^cd	33.10^bc	33.67^bc	37.23^bcd	32.23^b	15.37^a	0.342	< 0.001
Week 60	42.00^bcd	41.03^bc	49.37^d	42.67^bcd	44.57^bcd	44.20^bcd	38.63^bc	39.40^bc	40.87^bc	46.20^cd	44.97^bcd	37.23^b	21.07^a	0.447	<0.001
Week 64	28.67^ab	37.73^b	38.27^b	40.53^b	38.87^b	37.83^b	37.37^b	40.70^b	34.70^b	37.47^b	30.80^ab	32.90^ab	20.70^a	0.735	<0.001
Week 24–28	45.93^bc	53.41^e	49.16^cde	48.15^c	50.15^cde	48.8^cd	48.88^cde	53.08^de	43.55^b	47.01^bc	49.16^cde	42.65^b	24.53^a	0.261	<0.001
Week 32–64	38.98^bc	42.47^cd	43.35^d	42.66^cd	43.03^d	42.55^cd	41.35^cd	44.18^d	36.83^b	41.14^cd	43.54^d	37.1^b	21.5^a	0.218	<0.001
Week 24–64	40.24^bc	44.46^de	44.4^de	43.65^de	44.33^de	43.68^de	42.72^cde	45.79^de	38.05^b	42.2^cd	44.56^de	38.1^b	22.05^a	0.193	<0.001
Eggshell thickness (mm)
Week 24	0.32^abc	0.32^abc	0.32^abc	0.32^ab	0.31^a	0.32^abc	0.34^bc	0.32^ab	0.32^ab	0.34^c	0.31^ab	0.32^abc	0.36^d	0.001	<0.001
Week 28	0.33^ab	0.31^a	0.32^ab	0.35^b	0.31^a	0.30^a	0.33^ab	0.32^ab	0.32^ab	0.30^a	0.30^a	0.30^a	0.39^c	0.002	<0.001
Week 32	0.32^bc	0.30^abc	0.30^ab	0.33^c	0.32^abc	0.31^abc	0.31^abc	0.30^abc	0.32^abc	0.31^abc	0.32^abc	0.29^a	0.37^d	0.001	<0.001
Week 36	0.29^a	0.28^a	0.29^a	0.28^a	0.29^a	0.28^a	0.31^a	0.29^a	0.30^a	0.30^a	0.29^a	0.30^a	0.35^b	0.001	<0.001
Week 40	0.24^ab	0.25^ab	0.23^a	0.27^b	0.24^ab	0.23^a	0.27^b	0.24^ab	0.23^a	0.24^ab	0.23^a	0.22^a	0.30^c	0.002	<0.001
Week 44	0.24^a	0.21^a	0.25^a	0.22^a	0.26^ab	0.24^a	0.24^a	0.23^a	0.22^a	0.23^a	0.37^b	0.23^a	0.30^ab	0.007	0.001
Week 48	0.29^ab	0.28^ab	0.29^ab	0.28^ab	0.31^bc	0.29^ab	0.31^bc	0.29^ab	0.30^ab	0.31^bc	0.27^a	0.30^ab	0.33^c	0.002	<0.001
Week 52	0.29^c	0.28^abc	0.28^ab	0.30^c	0.29^abc	0.28^a	0.29^bc	0.29^abc	0.29^abc	0.29^abc	0.28^ab	0.28^ab	0.33^d	0.001	<0.001
Week 56	0.31^ab	0.30^ab	0.31^ab	0.31^b	0.30^ab	0.29^ab	0.30^ab	0.29^ab	0.28^a	0.29^ab	0.29^ab	0.29^ab	0.36^c	0.002	<0.001
Week 60	0.32^bc	0.30^abc	0.29^ab	0.31^abc	0.30^abc	0.28^a	0.30^abc	0.33^c	0.30^abc	0.31^abc	0.29^ab	0.30^abc	0.29^ab	0.002	0.001
Week 64	0.31^de	0.29^abcd	0.29^abcd	0.30^cde	0.29^abcd	0.28^a	0.30^abcd	0.31^bcd	0.29^abc	0.30^abcd	0.28^ab	0.29^abc	0.33^e	0.001	<0.001
Week 24–28	0.32^ab	0.31^ab	0.32^ab	0.33^b	0.31^a	0.31^ab	0.33^b	0.32^ab	0.32^ab	0.32^ab	0.31^a	0.308^a	0.37^c	0.002	<0.001
Week 32–64	0.29^b	0.28^ab	0.28^ab	0.29^a	0.29^ab	0.28^a	0.29^b	0.28^ab	0.28^ab	0.29^ab	0.29^a	0.28^ab	0.33^c	0.001	<0.001
Week 24–64	0.30^c	0.28^abc	0.29^abc	0.30^a	0.29^abc	0.28^a	0.30^c	0.29^abc	0.29^abc	0.29^a	0.29^abc	0.28^ab	0.34^d	0.001	<0.001
Yolk color
Week 24	6.83^ab	7.07^ab	7.03^ab	6.83^ab	7.20^b	7.10^ab	6.67^a	6.93^ab	6.97^ab	7.03^ab	6.80^ab	6.87^ab	7.00^ab	0.026	0.016
Week 28	7.60	7.83	7.33	7.53	7.70	7.66	7.70	7.86	7.56	7.60	7.80	7.53	7.96	0.065	0.897
Week 32	7.40^abc	7.60^abcd	7.40^abc	7.20^a	7.47^abcd	7.40^abc	7.87^cd	7.40^abc	7.70^bcd	7.53^abcd	7.77^cd	7.90^d	7.23^ab	0.041	0.014
Week 36	6.93	6.90	7.03	7.10	6.83	6.96	7.00	7.03	6.93	6.83	6.93	6.76	7.00	0.020	0.101
Week 40	7.37^b	7.33^b	7.23^ab	7.37^b	7.27^ab	7.00^ab	7.30^b	7.03^ab	7.33^b	7.20^ab	7.17^ab	6.27^a	7.43^b	0.204	0.302
Week 44	7.27^abcd	7.03^abcd	7.70^cd	7.57^bcd	7.47^bcd	6.80^abc	7.43^abcd	7.37^abcd	7.90^d	7.40^abcd	6.63^ab	6.50^a	7.60^cd	0.054	<0.001
Week 48	6.66	6.86	6.56	6.83	6.60	6.63	6.63	6.73	6.53	6.43	6.56	6.46	6.66	0.041	0.699
Week 52	6.90	6.93	6.90	6.73	7.13	6.60	6.96	6.96	6.90	6.86	6.83	6.70	7.00	0.031	0.121
Week 56	7.50	7.56	7.33	6.76	6.76	6.96	7.83	7.56	7.00	7.73	6.60	7.30	8.20	0.100	0.075
Week 60	7.27^ab	7.43^ab	6.97^a	6.93^a	8.17^b	7.27^ab	7.17^ab	7.63^ab	7.83^ab	7.40^ab	7.93^ab	7.83^ab	7.47^ab	0.059	0.001
Week 64	6.40	6.96	5.86	6.36	6.06	6.80	6.23	6.60	5.70	5.96	6.86	6.76	6.00	0.099	0.200
Week 24–28	7.22	7.45	7.18	7.18	7.45	7.83	7.18	7.4	7.27	7.32	7.30	7.20	7.48	0.034	0.598
Week 32–64	7.08	7.18	7.00	6.98	7.37	6.94	7.16	7.15	7.09	7.04	7.03	6.94	7.18	0.034	0.501
Week 24–64	7.1	7.23	7.03	7.02	7.39	7.01	7.16	7.19	7.12	7.09	7.08	6.99	7.23	0.027	0.232
Eggshell strength (g)
Week 24	4,742.23^bc	4,618.68^abc	4,370.22^abc	4,271.21^ab	4,555.78^abc	4,218.32^a	4,454.00^abc	4,426.92^abc	4,201.88^a	4,630.39^abc	4,143.69^a	4,794.39^c	5,682.55^d	28.257	<0.001
Week 28	4,643.33^a	4,464.12^a	4,341.01^a	4,463.67^a	4,541.43^a	4,371.07^a	4,534.26^a	4,506.36^a	4,345.50^a	4,516.15^a	4,323.43^a	4,534.92^a	5,780.72^b	25.836	<0.001
Week 32	4,544.43^a	4,309.54^a	4,311.80^a	4,656.12^a	4,527.08^a	4,523.81^a	4,614.52^a	4,585.79^a	4,489.11^a	4,401.91^a	4,503.16^a	4,275.45^a	5,878.88^b	45.483	<0.001
Week 36	4,026.00^a	3,970.38^a	4,062.08^a	3,952.52^a	4,301.12^a	3,826.52^a	3,973.15^a	3,944.00^a	4,200.36^a	4,093.69^a	3,771.42^a	4,186.64^a	5,611.31^b	31.173	<0.001
Week 40	3,791.7^a	3,451.91^a	3,824.23^a	4,137.67^a	3,800.71^a	3,757.72^a	3,747.61^a	3,974.41^a	3,846.38^a	3,727.38^a	3,655.66^a	3,566.53^a	5,130.76^b	48.385	<0.001
Week 44	4,526.65^a	4,479.55^a	4,242.19^a	4,384.88^a	4,309.40^a	4,291.50^a	4,376.32^a	4,400.87^a	4,340.34^a	4,445.71^a	4,313.75^a	4,370.62^a	5,761.32^b	36.444	<0.001
Week 48	4,468.42^a	4,464.10^a	4,232.69^a	4,444.49^a	4,339.04^a	4,256.71^a	4,391.93^a	4,304.73^a	4,312.87^a	4,389.83^a	4,372.23^a	4,280.91^a	5,737.98^b	22.389	<0.001
Week 52	4,144.41^a	4,116.02^a	4,017.18^a	4,215.60^a	4,154.67^a	3,931.77^a	3,991.31^a	4,074.28^a	4,087.14^a	4,007.14^a	3,999.66^a	4,022.32^a	5,498.75^b	38.339	<0.001
Week 56	3,521.55^a	3,739.07^ab	4,141.19^ab	3,896.31^ab	4,296.57^b	3,652.91^ab	3,822.31^ab	3,895.22^ab	3,704.24^ab	3,512.24^a	4,001.39^ab	3,790.55^ab	4,314.62^b	38.919	0.001
Week 60	3,877.91^ab	3,464.32^ab	3,810.24^ab	3,682.98^ab	4,095.53^b	3,751.46^ab	4,070.36^b	3,212.38^a	3,800.83^ab	3,611.13^ab	3,745.39^ab	3,528.41^ab	5,100.50^c	47.864	<0.001
Week 64	3,103.58^a	2,655.36^a	2,398.47^a	3,797.38^ab	3,316.25^ab	3,181.29^ab	2,723.72^a	2,664.42^a	2,516.80^a	2,787.79^a	2,743.31^a	3,745.63^ab	4,739.58^b	91.664	<0.001
Week 24–28	4,692.78^a	4,541.40^a	4,355.62^a	4,367.44^a	4,548.60^a	4,294.70^a	4,494.13^a	4,466.64^a	4,273.69^a	4,573.27^a	4,233.56^a	4,664.66^a	5,731.64^b	23.27	<0.001
Week 32–64	4,000.52^a	3,850.03^a	3,893.34^a	4,129.78^a	4,126.71^a	3,908.19^a	3,967.92^a	3,895.13^a	3,922.01^a	3,886.32^a	3,900.67^a	3,974.12^a	5,308.19^b	19.307	<0.001
Week 24–64	4,126.39^a	3,975.74^a	3,977.40^a	4,172.99^a	4,203.42^a	3,978.47^a	4,063.59^a	3,999.04^a	3,985.95^a	4,011.22^a	3,961.19^a	4,099.67^a	5,385.18^b	16.795	<0.001

Values in a row with different superscripts differ significantly (P<0.05).
Results are mean with 6 replicates per strain.
C, D: Korean Rhode Island; F, K: Korean Leghorn; Y: Korean domestic chicken.
SEM, standard error of the means.