Experimental design and animals
Three hundred and eight day-old male broiler chicks of Indian River strain were purchased
from the Ceylon Grain Elevators PLC (Prima Group) and assigned into seven dietary
treatments in a complete randomized design. After two weeks of brooding period in the
electrically heated battery brooder, each group was divided into four equal replicates to have
eleven chicks per replicate. The chicks were housed in floor pens (1 ft2/bird) after brooding.
The brooder temperature was maintained at 32 °C during the first week using electric bulbs
and gradually decreased thereafter by switched off the lights during day times while