Effect of Photoperiod on Early Growth and Feed Conversion in the Chukar Partridge

In three separate experiments in 1975 and 1976, growth rate, feed consumption, and mortality were studied in the chukar partridge (Alectoris gracea) kept under constant light, or under cycles of intermittent daily light of different intensities. In experiments 1 (1975) and 2 (1976), 471 and 480 chicks, respectively, were divided into four main groups and given either 12, 16, 20, or 24 hr of continuous incandescent light per day. Beginning at 2 weeks of age, half the chicks in each of the four light treatments were given a reduction of 2 hr light per day every 2 weeks. Those in the remaining half were continued on their original light schedule. In experiment 3 (1976), 400 chicks were divided into eight groups and given either continuous or intermittent light of high (40 lux) or low (4 lux) intensity. The light treatments were continuous, (1L:1D) 12 cycles per 24 hr, (2L:2D) six cycles per 24 hr, and (4L:4D) three cycles per 24 hr. Chicks kept under constant light regimens of continuous or (20L:4D) in experiments 1 and 2 were significantly (P<.05) heavier at 8 weeks of age than comparable birds kept on shorter photoperiods. In experiment 3, birds kept under light regimens of continuous or 12 cycles of (1L:1D) per 24 hr were significantly (P<.05) heavier at 12 weeks of age than comparable birds kept under intermittent light cycles with dark periods longer than 1 hr per cycle. Feed conversion varied among light treatments, but was generally better under continuous or (20L:4D) in experiments 1 and 2, or under continuous or 12 cycles of (1L:1D) per 24 hr in expriment 3. Mortality also varied, among light treatments and averaged about 4% for all tests. It is assumed that strains of chukar partridge selected specifically for rapid growth would respond most favorably to the longer photoperiods, or to the shorter energy-saving photoperiods of (1L:1D) given in 12 cycles per 24 hr.