Potential for Midnight Lighting to Influence Development of Growing Leghorn Pullets

Abstract

Three experiments were conducted to study the effect of a 2-h midnight lighting supplement on growth and development of Shaver White pullets grown on 8- or 12-h d. In all trials, each treatment was tested with 12 replicate groups of 10 caged pullets. In experiment 1, control birds were fed mash diets and grown on 12 h of light from 6:00 a.m. to 6:00 p.m. In another treatment, pullets received 2 h of light, from midnight to 2 p.m. throughout growing to 18 wk. In six other treatments, pullets received or were taken off the midnight lighting at 4, 8 or 12 wk of age. Experiments 2 and 3 were designed in the same way, although the control daylength was 8 h. In experiment 2, pullets received crumbled diets, and in Experiment 3, mash diets were used. The midnight lighting had only minor effects on feed intake and BW. Few important differences were seen when the control daylength was 12 h. Effects were more beneficial when an 8-h daylength was used, especially when using mash diets. The midnight lighting was obviously stimulatory to sexual development, even for 8-wk-old pullets. The highest rate of early egg production occurred when pullets were first subjected to midnight lighting at 12 wk of age. It is concluded that midnight lighting has quite minor effects on growth and feed intake of pullets grown under moderate temperatures. However, the lighting is stimulatory to sexual maturation, and subsequent studies will detail the performance of these birds in the layer house, with particular attention given to any effects rearing treatment has on egg size.