White Leghorn hens (360) were randomly allotted at cage densities of 3, 5 and 7 birds/cage (929, 557 and 412 cm2/bird) in a house at ambient temperature for an experimental period of 14 days. Three dietary energy levels (2.66, 2.86 and 3.07 kcal ME[metabolizable energy]/g) were formulated with the addition of 0, 4 and 8% tallow to the basal diet. The feeding levels used were ad lib 80, 60 and 40 g/bird per day. Maintenance feed and maintenance ME requirements/kg physiological body weight (PBW) were significantly increased as the number of birds per cage increased from 3 to 7. There were no dietary effects on the above parameters. Energy retention (ER) per PBW and egg output (g/bird per day) were significantly reduced by increasing bird density. There was a reduction in egg production. Protein consumptions were above the accepted minimum levels of 16.5 g/bird per day. Energetic efficiencies, measured as ME, converted to net energy (NE) were 57.75, 56.20 and 62.72% for the 3, 5 and 7 birds/cage group, respectively. A significant improvement in energetic efficiency was observed with 8% addition of fat.
