Table 2.

Effects of photoperiods on body weight and period body gain in broilers during wk 1 to 4 (d 14–43) postlight treatments.

Treatment	D 14	D 20	D 35	D 43	D 15–43
	BW (g)	BW (g)	BW (g)	BW (g)	AWG (g/d)
12L:12D	393.3	769.0B	2278.6a	3304.4a	100.4a
16L:8D	388.2	774.4AB	2216.6ab	3245.6ab	98.5a
18L:6D	388.1	779.1AB	2236.2ab	3206.2b	97.2ab
20L:4D	406.5	784.7A	2198.1b	3156.8c	94.8b
SEM	7.2	9.7	26.7	32.6	1.5
P value	0.685	0.062	0.022	0.006	0.047

Means within a column with different superscripts are different at:

^A,B0.05 ≤ P < 0.01.

^a–cP ≤ 0.05.

All means are reported as means ± SEM, n = 6 at 12 birds (2 birds/pen × 6 pens).

Abbreviations: AWG, average daily weight gain; BW, body weight.