Table 2. Effect of slack density and nutrient levels on growth performance in Korean native chickens

Treatment¹		Body weight (g/birds)		Weight gain² (g/birds)				Feed intake² (g/birds)				FCR²
SD	EL	Initial	Final	S	G	F	O	S	G	F	O	S	G	F	O
14 ×	Low	38.12	1,863^ab	642^b	653	530^ab	1,824^ab	1,448^a	1,803	1,638^a	4,890^a	2.26^a	2.76	3.09^ab	2.68^a
14 ×	High	38.16	1,958^a	685^a	653	581^a	1,920^a	1,433^ab	1,744	1,608^ab	4,786^ab	2.09^b	2.67	2.77^b	2.49^b
16 ×	Low	38.28	1,793^b	622^b	634	502^b	1,755^b	1,404^ab	1,746	1,582^b	4,733^bc	2.26^a	2.77	3.15^a	2.70^a
16 ×	High	38.23	1,873^ab	678^a	620	536^ab	1,835^ab	1,353^b	1,700	1,558^b	4,611^c	2.00^b	2.74	2.91^ab	2.51^b
14		38.08	1,950	663	653	556	1,872	1,441	1,774	1,623	4,838	2.17	2.72	2.92	2.58
16		38.25	1,878	650	626	519	1,795	1,378	1,723	1,570	4,672	2.12	2.75	3.02	2.60
	Low	38.20	1,828	632	642	516	1,790	1,426	1,775	1,610	4,811	2.26	2.76	3.12	2.69
	High	38.19	1,916	682	637	559	1,877	1,393	1,722	1,583	4,698	2.04	2.70	2.83	2.50
SEM³		0.03	18.71	7.68	8.27	10.48	18.71	12.75	15.11	9.66	29.49	0.03	0.02	0.05	0.02
P-vlaue⁴
SD		0.125	0.033	0.394	0.097	0.081	0.032	0.032	0.009	0.092	0.002	0.493	0.439	0.346	0.721
EL		0.973	0.013	<.000	0.763	0.035	0.013	0.199	0.081	0.173	0.052	<.000	0.218	0.008	<.000
SD × EL		0.519	0.751	0.468	0.755	0.606	0.753	0.361	0.814	0.826	0.777	0.239	0.500	0.681	0.969

Means in same rows with different superscripts are significantly different (P<0.05).
SD: stock density (birds/m²); EL: energy levels (ME kcal/kg): High: starter (3,150), grower (3,200), final (3,250); Low: starter (2,950), grower (3,000), final (3,050).
S: starter (0~35 d); G: growth (36~57 d); F: final (58~70 d); O: overall (0~70 d).
SEM: standard error of means.
SD: stock density; EL: energy levels; SD × EL: stock density × energy levels.