The Effects of Light Intensity During Rearing on Brown- and White-Feathered Egg Strain Pullets’ Use of Space, Behaviour, and Health

Abstract

This study aimed to determine the effects of light intensity (L) and strain (S) on growth, behaviour, frequency and success of jumping between structures, bone health, and welfare of pullets reared in a perchery. Three L (10, 30, or 50 lux, provided by white LED lights) and two Lohmann S (Brown-Lite (LB) and LSL-Lite (LW)) were tested. Pullets were floor reared in pens within light tight rooms from 0 to 16 weeks of age (wk). Each pen contained a system of four parallel perches, a ramp, drinker line, and two tube feeders. Data collected included body weight (BW), behaviour, jumping frequency and success, fear and stress response, keel bone damage (KBD), breast muscle weight, tibia bone characteristics and strength, and mortality. L did not affect BW, aggression, jumping success, fear, stress, KBD, breast muscle weight, tibia bone characteristics and strength, or mortality. At 13 and 16 wk, pullets reared in 50 lux spent more time preening than 10 lux pullets. At four wk, pullets reared in 30 and 50 lux had higher jumping frequency than 10 lux pullets, however jumping success did not differ. LB pullets had a higher BW than LW pullets at eight and 16 wk. Throughout the experiment, LB pullets spent more time pecking at litter and walls than LW pullets, while LW pullets spent more time resting and preening. LW pullets performed more jumps than LB pullets and were equally as successful in navigational jumps. S did not affect aggression, however LB pullets had higher fear and heterophil/lymphocyte ratio, suggesting S characteristic differences. S did not affect KBD. LB pullets had heavier breast muscle and tibia, however LW pullets had a proportionally higher breast muscle yield and thicker and stronger tibia. Mortality was higher in LW pullets than LB pullets in the first wk. The results suggest that pullets could navigate their environment safely under the Canadian industry standard of 10 lux. Higher L at 30 or 50 lux may have a minor improvement on welfare by increasing bird activity. Conclusively, these light intensities can prepare pullets for navigating complex environments during the laying phase.