Newly hatched leghorn breeder chicks (averaging 38.5 g body mass) housed in shipping containers were subjected to four limited feeding regimens for a three-day (3-d) period. The chicks were then raised for five days with adlibitum access to feed and nipple drinkers. For the 3-d treatment, the chicks received an average of 2.0, 2.5, 3.0, or 3.5 g starter feed (20.5% protein and 12,754 kJ/kg ME) and twice as much Aqua-Jel® (a water supplement) (AJ) placed directly on the honeycomb bedding of the containers. Air temperature at the chick level was maintained at 29.1 ± 0.2°C. Relative humidity was 28 to 37% during the treatment and 31 to 55% during the subsequent growth period. A photoperiod of 12L:12D cycle was provided throughout the experimental period.

The 3-d mortality rate (1.0 to 1.7%) and body mass loss (15.4 to 16.8% initial value) showed no significant difference (P > 0.05) among the treatments. Metabolic rate was also not significantly different (P > 0.05) among the treatments, although it was generally proportional to the level of nutrient supply. Lighting conditions had a major impact on the chick energetics. Specifically, moisture production (MP) averaged 5.6 to 7.2 g/(kgÿh) during the light period, but 3.8 to 5.1 g/(kgÿh) during the dark period (P < 0.05). Total heat production (THP) averaged 8.3 to 9.2 W/kg during the light period and 6.0 to 6.8 W/kg during the dark period. The reduced metabolic rate in the darkness could be a useful avenue for conserving energy and, thus, body mass loss of fasting chicks during prolonged overseas shipment.

The 8-d mortality (2.4 to 3.1%) and the 5-d subsequent body mass gain (42.4 to 45.8% of the initial value) of the chicks also showed no significant difference (P > 0.05) among the treatments. Thus a supply of up to 3.5 g feed and 7 g AJ per chick during 72-h post-hatch shipments seems insufficient to achieve a “normal”, postshipment chick performance. Energetic responses during the 5-d subsequent growth period were similar for all the treatments. Specifically, THP averaged 21.3 W/kg during the light period and 14.9 W/kg during the dark period (P < 0.05). The corresponding MP was 23.6 g/(kgÿh) and 15.0 g/(kgÿh) (P < 0.05), respectively.