# Evaluation of Pulsed Alternating Wavelength System Lighting on the Welfare Quality and Serotonin Turnover of Commercial Laying Hens Throughout a Lay Cycle

## TL;DR

This study evaluates a new lighting system (PAWS) on laying hens' welfare and finds it may improve both physiological and physical health compared to traditional lighting.

## Contribution

The study introduces and validates the Pulsed Alternating Wavelength System (PAWS) as a lighting type that may improve laying hen welfare.

## Key findings

- One PAWS recipe reduced serotonin turnover, indicating improved physiological welfare.
- Another PAWS recipe reduced keel bone damage, indicating improved physical welfare.
- Most welfare parameters were influenced by age rather than lighting type.

## Abstract

Artificial light sources are utilized in the laying hen industry to maintain proper growth and egg production. The Pulsed Alternating Wavelength System (PAWS) is a new lighting type that may benefit laying hen production and welfare, but needs to be validated. This study evaluated the effects on neurotransmitter turnover (physiological markers of welfare) and physical welfare quality of commercial laying hens housed in conventional cages under two PAWS recipes or fluorescent lights throughout a lay cycle. The majority of welfare parameters were influenced by age and not lighting type. However, one PAWS recipe had reduced serotonin turnover, and the other PAWS recipe had reduced keel bone damage. These are both indicators of improved physiological and physical welfare compared to the control hens. The PAWS lighting may be beneficial to the welfare of conventionally caged laying hens and warrants further research, especially in alternative housing systems.

Laying hens require lighting for proper development and reproduction. There is limited research on the effects that lighting types have on birds’ welfare quality. A novel lighting source, Pulsed Alternating Wavelength System (PAWS), is being evaluated in the industry that claims to improve birds’ growth rate, decrease age at first egg, and decrease aggressive and nervous behaviors. Understanding how PAWS effects hen’s welfare, both physically and physiologically, is critical if this technology is to be adopted by industry. The project evaluated the effects of two PAWS lighting recipes on neurotransmitter turnover and welfare quality of commercial, conventionally caged laying hens. Three flocks of White leghorn hens (control [fluorescent lights] and two PAWS flocks [PAWS1 and PAWS2]) were sampled from 22 to 70 weeks of age, depending on the flock. The physical welfare of 50 hens per flock and neurotransmitter turnover of 10 hens per flock were assessed at each timepoint. The majority of welfare quality parameters were influenced by age as opposed to lighting type. No differences in dopamine turnover were observed. The hens housed under PAWS1 had reduced serotonin turnover, thus increased serotonin activity, and PAWS2 hens had improved keel bone damage scores; both indicative of improved welfare compared to control hens. The novel lighting may be beneficial to layer welfare, which may lead to increased longevity and productivity. Implementation in cage-free housing should be explored to delve into potential behavioral differences that could further influence welfare outcomes.