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

Animals · 2026-01-13

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.

Performance, Skeletal traits, and welfare indicators of four laying hen strains in aviary housing under common management

Poultry Science · 2026-01-28

The transition from conventional cages to cage-free aviary systems in egg production presents unique challenges for performance, welfare, and skeletal health of laying hens. While extensive data exists for conventional systems, aviary systems require comprehensive investigation due to larger colony sizes and increased opportunities for vertical and lateral movement. This study evaluated the production, welfare, and skeletal characteristics of four commercial laying hen hybrids, two brown egg (brown) and two white egg (white) strains, in an aviary housing system under common management. Brown strains were consistently heavier with larger tibia volume, surface area, and mineral content compared to white strains. All 4 strains achieved at least 91 % hen day egg production, with white strain C having 8 percentage point higher production rates throughout the majority of lay. Feather coverage deteriorated as all hens aged, but white strains, especially strain C, had more frequent feather damage during assessments. Brown strains had more incidence of keel damage based on manual palpation. However, visual inspection of excised keel bones revealed brown strain B had fewer fractures than all other strains, though 90 % of the keel bones had fractures, frequently in the tip. These findings reveal significant strain-specific differences in production, skeletal health, and welfare in aviary systems. Our use of common management may have hindered hens from achieving their full genetic potential; thus, tailoring management and housing practices to accommodate these differences is crucial for successful cage-free egg production and hen welfare.

Electrocoagulation-treated poultry wastewater sludge as a sustainable feed resource for black soldier fly larvae

Scientific Reports · 2026-01-30

Black soldier fly larvae (BSFL) are an excellent protein source that can serve as a sustainable and nutritious diet to support the growth of aquaculture species. They could be an affordable and eco-friendly alternative to traditional fishmeal. BSFL can be cultivated using wastewater sludge derived from various domestic and industrial wastewater sources. This study focused on using egg-washing and poultry-slaughtering wastewater sludges to grow BSFL. The solid portion of the BSFL diet consisted of the Gainesville Diet, in which moisture was supplied from various wastewater treatment sludge and tap water sources. Electrocoagulation and flocculation methods were employed to treat wastewater from egg washing and poultry slaughter. Aluminum (Al) and iron (Fe) electrodes were used in electrocoagulation, and the pH, electric current, and treatment time for the wastewater samples were optimized. Electrocoagulation of egg-washing wastewater showed high treatment performance, with Al electrodes removing up to 81% COD, 62% ammonia, and 91% phosphate, while Fe electrodes removed 84.4% COD and 92% ammonia. In duck-slaughtering wastewater, Al electrodes provided up to 98.21% COD removal, and both Al and Fe electrodes achieved > 99% phosphate removal under optimized conditions. Ammonia removal reached ~ 99% using Al electrodes at pH 9 and 26.04 mA cm⁻². Given the remaining organic load and future perspectives, integrating electrocoagulation with anaerobic digestion could further reduce COD while enabling biogas recovery. The highest average total solids (32.00 mg/L) and inorganic solids (22.43 mg/L) were found in duck-slaughtering wastewater sludge treated with Fe electrodes. Flocculation resulted in an average of 16 mg/L of volatile solids. Larvae fed on sludge from both treatment methods showed an average weight gain equivalent to 5-8-fold increase in body weight, with the highest weight gain (corresponding to a 7.7-fold increase) achieved from duck-slaughtering sludge treated using the electrocoagulation method. The proportion of larvae reaching the pupation stage was examined during the 15-day observation period. Diet treatment based on duck slaughtering wastewater sludge using Al electrode showed the lowest proportion of individuals reaching the maturation stage.

Age effects on measurements of hypothalamic-pituitary-adrenal axis activation in laying hens

Poultry Science · 2025-01-23 · 2 citations

Stress is a complex but poorly understood topic, especially in commercial poultry species. However, hypothalamic-pituitary-adrenal axis (HPA) activation through either exogenous glucocorticoid or adrenocorticotropic hormone (ACTH) administration in birds generally results in increased circulating glucocorticoid levels, often associated with stress. HPA activation responses are complicated by physiological changes while the birds mature and enter production. The objective of this study was to evaluate changes in HPA activation in relation to physiological age of the bird. Ten each of Lohmann LSL-Lite hens received either a saline-mannitol or synthetic ACTH (ACTH1-24) injection at 6, 17, and 26 weeks of age (WOA). Blood was collected prior to ACTH injections, and one-, and two-hours post-injection. From these blood samples, white blood cell (WBC) differential counts, heterophil:lymphocyte (H:L) ratios (N = 10/treatment), and corticosterone and cortisol levels were measured using a high-performance liquid chromatography (HPLC) system coupled to a mass spectrometer (MS/MS) (N = 5/treatment). At 26 weeks of age, egg albumen samples were collected and corticosterone and cortisol measured using an HPLC system coupled to a mass spectrometer (MS/MS) (N = 5/treatment). In this study, plasma cortisol was unaffected by treatment and egg albumen corticosterone and cortisol were below detectable limits at all time points for both treatments. Plasma corticosterone increased 1 h after injection in the ACTH group at all ages; this was significant at 17 WOA (P < 0.0001). The H:L ratio was not affected by treatment but heterophils increased and lymphocytes decreased in the ACTH group compared to the control group, this difference was observed at 26 WOA (P < 0.0004). The results of this study suggest that the H:L ratio is not an accurate measure of acute HPA activation during the pullet phase and that plasma cortisol and albumen corticosterone and cortisol are not an accurate measure of acute HPA activation during the pullet or adult phases. Corticosterone may have some utility in capturing a physiological stress response in pullets and adult hens but requires further investigation.

Pulsed alternating wavelength system lighting does not negatively impact production or welfare but reduces dopamine activity and may improve bone growth in grow-out Pekin ducks

Poultry Science · 2025-01-23 · 4 citations

The production and welfare of Pekin ducks can be affected by the lighting type they are housed under. There is no standard lighting system in industry and little data evaluating effects of different light systems on duck production and welfare. Pulsed Alternating Wavelength System (PAWS) is a novel LED technology that delivers multiple wavelengths of light in pulsating patterns. This study aimed to determine the effects of PAWS on brain serotonin turnover and skeletal quality in ducks. Ducks housed under PAWS were hypothesized to have lower brain serotonin turnover and equal bone quality compared to those housed under control lights (fluorescent with digital ballasts, 4500K, ∼40 lux). Ducks were placed in floor pens under PAWS or control lighting (1200 ducks/pen, n = 4 pens/treatment) at day of hatch until processing at 30 days of age (DOA). Body weights and feed intake were monitored weekly. Brains, femurs, tibiae, and humeri were collected on days 7, 14, 21 and 29 (n = 6 ducks/age/lighting type). Brain serotonin and metabolites were measured. Bone length, width, breaking strength, and ash were determined. Serotonin data were analyzed using 2-way ANOVA for age and lighting treatment with a post-hoc Fisher's LSD test. Bone data were analyzed with independent t-tests between treatments within each age. Ducks housed under PAWS were heavier by 29 DOA than controls (P < 0.001) with no differences in feed conversion. Brain analyses revealed no differences in serotonin turnover between lighting types. Early interstitial growth of PAWS femur and tibia was increased (P < 0.05), and PAWS femurs had increased bone mineral content at 29 DOA (P = 0.001). At 29 DOA, the PAWS humeri were wider than controls (P = 0.025) and had increased geometrical bone mechanical properties (P < 0.003), but no differences in breaking stress were evident. Results suggest that PAWS may have benefits for production traits and skeletal quality, however, a complete understanding of the welfare effects need further study.

The use of quantitative computed tomography for bone ash quantification may avoid euthanasia of young broiler chickens

Poultry Science · 2025-07-24 · 1 citations

The objective of the current study was to compare bone ash and digital bone mineral content (BMC) calculated from clinical quantitative computed tomography (QCT) in young broiler chickens. A total of 576 male broiler chickens (initial BW = 190 ± 17 g) on d 8 post hatching were allotted to the 6 experimental diets in a randomized complete block design. The 6 diets included a phosphorus (P)-deficient basal diet based on corn and soybean meal, basal diet plus 0.9 or 1.8 g/kg of inorganic P from monosodium phosphate (MSP), and basal diet plus 500, 1,000, or 2,000 FYT/kg of exogenous phytase. On d 11 post hatching, 7 birds from each cage were euthanized and the 5 remaining birds were euthanized on d 18. The entire left leg was collected from the bird with median weight from each cage on d 11 and 18. Digital BMC of femur and tibia in the collected whole left legs was estimated using clinical QCT scan. Subsequently, the tissues attached to the left legs were manually removed using a scalpel, and bone ash of femur and tibia was analyzed. An interaction between bone trait (bone ash or digital BMC) and MSP or phytase was not observed. There was no statistical difference in femur and tibia on d 11 and 18 between digital BMC and bone ash. In conclusion, clinical QCT may replace sacrificing birds for bone ash estimation in young broiler chickens irrespective of their bone mineralization status.

Environmental contamination and horizontal transmission of Salmonella Enteritidis among experimentally infected layer pullets in indoor cage-free housing

Poultry Science · 2025-05-03 · 3 citations

The persistence and transmission of the egg-associated pathogen Salmonella Enteritidis in laying flocks are significantly influenced by the poultry housing environment. The present study assessed environmental contamination and horizontal transmission of S . Enteritidis within groups of layer pullets in cage-free housing after infection just before the age of sexual maturity. In each of 3 trials, 144 pullets were transferred from a rearing facility at 15 wk of age and randomly distributed between 2 isolation rooms simulating commercial cage-free barns with perches and nest boxes (72 birds/room). One wk after placement in the containment facility, a proportion of the 72 pullets in each room were orally inoculated with approximately 6 × 10 7 cfu of S . Enteritidis: 1/3 in trial 1, 1/6 in trial 2, and 1/12 in trial 3. At 2 wk post-inoculation in each trial, samples of liver, spleen, and intestinal tract were collected from 40 uninoculated (contact-exposed) birds in each room for bacteriologic culturing to detect horizontal transmission of S . Enteritidis. At 6 intervals between inoculation and necropsy, 5 types of environmental samples (wall dust swab, nest box swab, perch swab, flooring substrate drag swab, and flooring substrate composite) were collected and cultured for S . Enteritidis. The overall frequencies of S . Enteritidis recovery from both environmental samples and internal organs from contact-exposed pullets after initial oral inoculation of 1/3 of the birds in each room (97 % and 75 %, respectively) were significantly greater than after initial infection of 1/6 of the birds (78 % and 58 %), and S . Enteritidis recovery from birds inoculated at a 1/12 proportion (10 % of environmental samples and 18 % of organs) was significantly lower than from the 1/6 inoculation group. Flooring substrate composites were the most efficient environmental sample type for all 3 trials combined (72 % positive), providing significantly better S . Enteritidis recovery than the least efficient samples (flooring substrate drag swabs; 53 % positive). These data suggest that a high frequency of environmental contamination may be an important contributor to horizontal transmission of S . Enteritidis infections among pullets in cage-free housing.

Autoclaving young broiler chicken bones for tissue removal may affect measured bone characteristics

Canadian Journal of Animal Science · 2025-01-01 · 1 citations

The objective was to compare the effects of autoclaving and manual cleaning on bone characteristics in broiler chickens. Birds were fed three diets with different concentrations of calcium and phosphorus. Tissue was removed by using a scalpel or autoclaving at 100 °C for 1 min from the entire left and right legs collected on d 11 and 18. Autoclaving decreased ( p &lt; 0.05) breaking strength and bone ash of femur and tibia except for bone ash of femur on d 18. In conclusion, autoclaving is not recommended for tissue removal from bones in young broiler chickens.

Research note: Pulsed alternating wavelength system (PAWS) may aid in the maintenance of laying hen skeletal quality throughout a lay cycle

Poultry Science · 2025-12-31

Adequate light is required for normal development of the skeletal system in laying hens. A novel lighting system, Pulsed Alternating Wavelength System (PAWS), has been developed for the poultry industry. Through production-specific lighting recipes, PAWS may improve the growth rate, welfare, and productivity of poultry species, including laying hens. Since the skeleton plays a crucial role in egg production, determining how PAWS can impact bone quality in laying hens is essential. The objective of this project was to evaluate the effects of two PAWS lighting recipes on the skeletal quality of commercial, conventionally-caged laying hens. Three flocks at a commercial facility housed under either control lighting (CON) or different PAWS recipes (PAWS1 or PAWS2) were followed throughout a lay cycle. The femur, tibia, and humerus were assessed for digital bone mineral density and content (dBMD; dBMC), and biomechanical properties from 3-point bending. At the post-peak production phase, PAWS1 did have greater femur flexural strength (P = 0.031) and greater humerus Young's modulus (P = 0.031) compared to CON hens. From peak to post-peak production, the tibia fracture force and flexural strength remained consistent in PAWS1 hens (P > 0.100), but declined in CON hens (P < 0.002). Hens exposed to PAWS1 had improved bone strength properties during post-peak production, and maintained structural integrity of the tibia while strength and integrity declined in CON hens. The PAWS2 bone quality properties were consistent from peak production to post-molt, with few exceptions, however, this was likely due to the act of molting rather than the lighting type. The novel lighting shows promise in improving layer bone quality, warranting research in cage-free environments.

Feeding black soldier fly larvae using wastewater treatment sludge: A zero-waste sustainable solution

Research Square · 2025-09-25