Each of the 4 experimental diets was offered to
birds in each of 16 individual pens in a randomized
complete block design. The room temperature was approximately
32°C at d 0 and was gradually reduced
to 20°C at the end of the study. A standard lighting
program for broilers was used, decreasing from 23:1 h
(light:dark) from 1 d old to 18:6 h at 7 d of age, which
was maintained until the end of the study