Table 2.

Energy utilisation of commercial free-range laying hens.

Main effect		GE intake, MJ	ME (DM feed basis), MJ/kg	MEi, kg/BW0.75	RE, kg/BW0.75	NE (DM basis), MJ/kg	HP/hen per d, MJ/kg	HP/hen per d, MJ/kg BW0.75	HI, MJ/kg BW0.75	NEi, MJ/kg BW0.75	NE/ME	RN/hen per d, g	RN, %	Total egg number/3 hens per 3 d	LR, %	Total egg mass/hen per d, g
RU	BW
Rangers		15.07	13.67	0.7975a	0.1904	9.59	0.965	0.607b	0.237a	0.5604	0.70	1.46a	45.6	8.210	91.30	60.80
Stayers		15.44	13.69	0.8517b	0.2150	9.41	0.9738	0.637a	0.267b	0.5850	0.71	1.59b	48.4	7.790	86.70	63.20
	Light	15.09	13.67	0.8537b	0.2245b	9.52	0.935a	0.629	0.259	0.5945b	0.69	1.54	48.2	8.460	94.00	63.19
	Heavy	15.41	13.69	0.7955a	0.1809a	9.48	1.003b	0.615	0.245	0.5509a	0.69	1.49	45.7	7.540	84.00	60.81
Two-way interaction (RU × BW)
Rangers	Light	14.64	13.80b	0.8243	0.2143	9.77b	0.9193	0.610	0.2400	0.5843	0.70	1.49	47.9	8.670	96.30	61.34
Rangers	Heavy	15.50	13.54ab	0.7708	0.1665	9.42ab	1.0113	0.6045	0.2345	0.5365	0.69	1.42	43.2	7.750	86.30	60.27
Stayers	Light	15.55	13.54a	0.8830	0.1953	9.27a	0.9515	0.6483	0.2783	0.6048	0.69	1.61	48.5	8.250	91.80	60.29
Stayers	Heavy	15.32	13.85ab	0.8203	0.2348	9.55ab	0.9940	0.6247	0.2547	0.5653	0.70	1.57	48.2	7.330	81.70	66.12
P-values
RU		0.477	0.850	0.025	0.192	0.190	0.652	0.005	0.005	0.192	0.318	0.023	0.076	0.373	0.373	0.988
BW		0.539	0.834	0.018	0.032	0.795	0.002	0.107	0.107	0.032	0.130	0.302	0.101	0.067	0.067	0.304
RU × BW		0.298	0.044	0.830	0.816	0.040	0.155	0.296	0.296	0.816	0.470	0.750	0.145	1.000	1.000	0.981

RU = range usage; BW = body weight; GE = gross energy; ME = metabolizable energy; ME_i = metabolizable energy intake; RE = retained energy; NE = net energy; HP = heat production; HI = heat increment; NE_i = net energy intake; RN = retained nitrogen; LR = laying rate.

Means were obtained from 4 replicate cages of 3 birds each.

^{a, b} Within a column, means with no common superscript are significantly different at P < 0.05.