Oxidative status: A general but overlooked indicator of welfare across animal species?

Because of their ubiquity, plasticity, and direct effects on the nervous system, markers of oxidative status may be of great value to assess animal welfare across species and conditions in the wild. However, welfare biologists have not yet seized this opportunity, possibly because the validity of these markers as welfare indicators remains questionable. A validation process was, therefore, performed here using a meta-analytical approach considering three conditions assumed to impair the welfare of animals. With very few exceptions, two of the four considered markers consistently varied across these negatively-valenced conditions. By highlighting the current underrepresentation of markers of oxidative status in animal welfare studies, and by concretely illustrating that some of these markers can consistently reflect negative affective states, this article aims to encourage biologists to include these physiological markers in their toolbox to better measure, monitor, and perhaps also improve the welfare of animals in their natural habitat.

Estimating the value of democracy relative to other institutional and economic outcomes among citizens in Brazil, France, and the United States.

How much do citizens value democracy? How willing are they to sacrifice their liberties and voting rights for growth, equality, or other social outcomes? We design a conjoint experiment in nationally representative surveys in Brazil, France, and the United States in which respondents choose between different societies that randomly vary in their economic outcomes (country income, income inequality, social mobility), political outcomes (democracy, public health insurance), and the level of personal income for each respondent. Our research allows us to estimate the respondents' willingness to trade off democracy for individual income (as well as other societal attributes). We find that, on average, individuals are strongly attached to democracy and a robust welfare state. They prefer to live in a country without free democratic elections only if their individual income multiplies by at least three times and in a country without public health insurance only if their individual income more than doubles. After estimating these preferences at the individual level for all respondents, we show that, although there is an authoritarian minority in all three countries, forming a nondemocratic majority (by offering more income and/or other goods to respondents) is very unlikely. Our findings imply that, contrary to a growing discussion about the crisis of democracy, liberal democratic values remain substantially robust in high and middle income democracies.

Using measures of race to make clinical predictions: Decision making, patient health, and fairness.

The use of race measures in clinical prediction models is contentious. We seek to inform the discourse by evaluating the inclusion of race in probabilistic predictions of illness that support clinical decision making. Adopting a static utilitarian framework to formalize social welfare, we show that patients of all races benefit when clinical decisions are jointly guided by patient race and other observable covariates. Similar conclusions emerge when the model is extended to a two-period setting where prevention activities target systemic drivers of disease. We also discuss non-utilitarian concepts that have been proposed to guide allocation of health care resources.

Explaining happiness trends in Europe.

In Europe, differences among countries in the overall change in happiness since the early 1980s have been due chiefly to the generosity of welfare state programs-increasing happiness going with increasing generosity and declining happiness with declining generosity. This is the principal conclusion from a time-series study of 10 Northern, Western, and Southern European countries with the requisite data. In the present study, cross-section analysis of recent data gives a misleading impression that economic growth, social capital, and/or quality of the environment are driving happiness trends, but in the long-term, time-series data, these variables have no relation to happiness.

Clinical HIV outcome trajectories associated with a history of child protective service out-of-home care: Longitudinal cohort findings with women living with HIV in Canada.

OBJECTIVES: Knowledge gaps exist regarding the effects of experiencing child protective services (CPS) out-of-home care (e.g. foster homes) among women with HIV. We examined whether CPS out-of-home care was associated with HIV clinical outcome trajectories among women with HIV in a longitudinal cohort study in Ontario, British Columbia, and Quebec, Canada. METHODS: At three timepoints across 5 years (2013-2018), we examined self-reported current antiretroviral therapy (ART) use and viral load (VL) detectability (>50 copies/mL). We used latent class growth analysis (LCGA) to identify trajectories of ART use and VL outcomes across study waves. LCGA identifies subgroups (classes) with similar trajectories within the sample. We assessed whether HIV outcome trajectories could be predicted by CPS history. We then conducted a mediation analysis to test whether a mental health latent construct mediated the association between CPS history and detectable VL. RESULTS: Nearly one-fifth (n = 272; 19%) of participants (n = 1422; mean age 42.8 years) reported CPS out-of-home care. Most participants (89%) were in classes that consistently used ART and had an undetectable VL. Individuals with CPS out-of-home care histories were twice as likely to have a consistently detectable VL (ß = 0.72, p = 0.02); there were no differences in ART use trajectories. In mediation analyses, we found an indirect path from CPS history to a consistently detectable VL via baseline mental health status (ß = 0.02, 95% confidence interval 0.005-0.04, p = 0.02), with a significant odds ratio (1.12, z = 2.43, p = 0.02). CONCLUSION: Among women with HIV in Canada, experiencing childhood CPS out-of-home care was associated with a reduced likelihood of achieving viral suppression, via poorer mental health.

The societal impact of individual placement and support implementation on employment outcomes for young adults receiving temporary health-related welfare benefits: a difference-in-differences study.

BACKGROUND: Individual placement and support (IPS) is an evidence-based practice that helps individuals with mental illness gain and retain employment. IPS was implemented for young adults at a municipality level through a cross-sectoral collaboration between specialist mental healthcare, primary mental healthcare, and the government funded employment service (NAV). We investigated whether IPS implementation had a causal effect on employment outcomes for all young adults in receipt of a temporary health-related rehabilitation (work assessment allowance, WAA) welfare benefit, measured at the societal level compared to municipalities that did not implement IPS. METHOD: We used a difference in differences design to estimate the effects of IPS implementation on the outcome of workdays per year using longitudinal registry data. We estimate the average effect of being exposed to IPS implementation during four-years of implementation compared to ten control municipalities without IPS for all WAA recipients. RESULTS: We found a significant, positive, causal effect on societal level employment outcomes of 5.6 (p = 0.001, 95% CI 2.7-8.4) increased workdays per year per individual, equivalent to 12.7 years of increased work in the municipality where IPS was implemented compared to municipalities without IPS. Three years after initial exposure to IPS implementation individuals worked, on average, 10.5 more days per year equating to 23.8 years of increased work. CONCLUSIONS: Implementing IPS as a cross sectoral collaboration at a municipality level has a significant, positive, causal, societal impact on employment outcomes for all young adults in receipt of a temporary health-related rehabilitation welfare benefit.

Cardiovascular physiology of decapod crustaceans: from scientific inquiry to practical applications.

Until recently, the decapod crustacean heart was regarded as a simple, single ventricle, contraction of which forces haemolymph out into seven arteries. Differential tissue perfusion is achieved by contraction and relaxation of valves at the base of each artery. In this Review, we discuss recent work that has shown that the heart is bifurcated by muscular sheets that may effectively divide the single ventricle into 'chambers'. Preliminary research shows that these chambers may contract differentially; whether this enables selective tissue perfusion remains to be seen. Crustaceans are unusual in that they can stop their heart for extended periods. These periods of cardiac arrest can become remarkably rhythmic, accounting for a significant portion of the cardiac repertoire. As we discuss in this Review, in crustaceans, changes in heart rate have been used extensively as a measurement of stress and metabolism. We suggest that the periods of cardiac pausing should also be quantified in this context. In the past three decades, an exponential increase in crustacean aquaculture has occurred and heart rate (and changes thereof) is being used to understand the stress responses of farmed crustaceans, as well as providing an indicator of disease progression. Furthermore, as summarized in this Review, heart rate is now being used as an effective indicator of humane methods to anaesthetize, stun or euthanize crustaceans destined for the table or for use in scientific research. We believe that incorporation of new biomedical technology and new animal welfare policies will guide future research directions in this field.

Longitudinal trajectories of suicidal ideation among child welfare-involved 7- to 12-year-old children.

BACKGROUND: Young children involved in the child welfare system (CWS) are at high risk for suicidal ideation (SI) at a time when overall rates of suicide death in this age group are rising. Yet risk factors for and changes in SI over time are poorly understood in this population. METHOD: We combined data from two large representative longitudinal studies of children involved in the United States CWS. We examined patterns of SI among children who were between ages 7 and 12 years at the initial survey wave (N = 2,186), assessed at three waves using a measure of SI in the past 2 weeks. We conducted a multinomial regression to understand the baseline demographic, child maltreatment, and mental health characteristics that distinguish the trajectories. RESULTS: There were eight different subgroups (Non-Ideators, Late Ideators, Boomerang Ideators, Delayed Ideators, Desisters, Boomerang Non-Ideators, Late Desisters, and Persisters). Differences in race, type of maltreatment, sex, and mental health symptoms were identified when comparing Persisters (SI at all three waves) to other groups. CONCLUSIONS: These findings can help researchers and practitioners to develop strategies for better identifying CWS-involved children who are in greatest need of suicide risk monitoring and intervention.

Assessing the Health and Welfare Benefits of Interventions Using the Wider Societal Impacts Framework.

OBJECTIVES: Health technology assessment bodies advocate capturing the value of interventions in terms of their benefits to health and broader welfare. The wider societal impacts (WSI) framework considers how changes in health alter a person's net contribution to society-that is, what they produce minus what they consume. In this research, we review this framework and explore the scope to differentiate WSI by equity-relevant sociodemographic characteristics. METHODS: This research updates previous calculations using publicly available data from population-based surveys in the United Kingdom. We then estimate for 199 chronic conditions: (1) WSI for the average person with the condition and (2) gain in WSI for an improvement of 0.1 in health-related quality of life score. RESULTS: The nature and availability of information varied across population-based surveys and precluded analyses to examine WSI by population subgroup. Our updated estimates mirrored earlier findings that consideration of the broader societal impacts of health would reprioritize interventions compared with assessment on health alone. For example, for the same improvement in health, a woman experiencing diseases of the circulatory system has the highest potential gain in WSI (£354/month) whereas a man experiencing HIV has the lowest potential gain (£233/month). CONCLUSIONS: The WSI framework provides a simple, indirect method to inform resource allocation decisions. Understanding the equity implications of this approach was hindered by differences in the information collected across population-based surveys. Findings demonstrate the potential reprioritization that may occur if the broader welfare benefits of health interventions were used to inform coverage decisions.

Patient Welfare Implications of Indication-Specific Value-Based Pricing of Multi-Indication Drugs.

OBJECTIVES: Indication-specific value-based pricing (ISVBP) is a mechanism that allows the prices of multi-indication drugs to vary across indications by aligning the drug prices with value. However, the overall impact of ISVBP on patients across indications is uncertain. This study examines the theoretical welfare effects of ISVBP for multi-indication drugs and compares consumer surplus under ISVBP and single pricing, the latter of which is based on the weighted average value. METHODS: We considered a healthcare system with government-negotiated drug prices based on the value of drugs. We assumed a drug with 2 indications and 1 relevant comparator for each indication. The value of the drug was uniformly distributed among the patients of each indication in the base case. We also considered alternative scenarios with exponentially and Pareto distributed drug values. Numerical simulations were conducted to explore potential settings where ISVBP was welfare-improving for patients compared with single pricing. RESULTS: The theoretical analysis showed that the consumer surplus change was strictly non-positive from single pricing to ISVBP. Therefore, it was not welfare-improving for patients in the settings of interest. Numerical simulations confirmed this result across various scenarios of value distributions. CONCLUSIONS: This study provides insights into the patient welfare implications of ISVBP for multi-indication drugs. We did not identify conditions under which ISVBP can enhance overall patient well-being, suggesting that it should be implemented cautiously. Future research should examine dynamic welfare implications related to innovation incentives because they may significantly affect population health in the future.

Social Decision-Making Analysis: A General Approach to Inform Decisions on Resources in the Public Sector.

OBJECTIVES: Public expenditure aims to achieve social objectives by improving a range of socially valuable attributes of benefit (arguments in a social welfare function). Public expenditure is typically allocated to public sector budgets, where budget holders are tasked with meeting a subset of social objectives. METHODS: Decision makers require an evidence-based assessment of whether a proposed investment is likely to be worthwhile given existing levels of public expenditure. However, others also require some assessment of whether the overall level and allocation of public expenditure are appropriate. This article proposes a more general theoretical framework for economic evaluation that addresses both these questions. RESULTS: Using a stylized example of the economic evaluation of a new intervention in a simplified UK context, we show that this more general framework can support decisions beyond the approval or rejection of single projects. It shows that broader considerations about the level and allocation of public expenditure are possible and necessary when evaluating specific investments, which requires evidence of the range of benefits offered by marginal changes in different types of public expenditure and normative choices of how the attributes of benefit gained and forgone are valued. CONCLUSIONS: The proposed framework shows how to assess the value of a proposed investment and whether and how the overall level of public expenditure and its allocation across public sector budgets might be changed. It highlights that cost-benefit analysis and cost-effectiveness analysis can be viewed as special cases of this framework, identifying the weakness with each.

Values Beyond "Health" in Budget-Constrained Healthcare Systems.

OBJECTIVES: Most current methods to value healthcare treatments only incorporate measures such as quality-adjusted life-years, combining gains in health-related quality of life and life expectancy in specific ways. Failure of these methods to recognize other dimensions of value has led to calls for methods to include additional values that are associated with the healthcare treatments but not captured directly by quality-adjusted life-years. This article seeks to provide methodologically sound ways to incorporate additional health-related outcomes, focusing on budget-constrained healthcare systems, in which using standard welfare economics methods are often eschewed. METHODS: The analysis develops standard extra-welfarist approaches to maximizing aggregate health, subject to fixed-budget constraints, using Lagrange multiplier methods. Then, additional valuable health-related outcomes, eg, reduced caregiver burden, real option value, and market- and non-market productivity are introduced. The article also introduces a social welfare function approach to illuminate how disability, disease severity and other equity-related issues can be incorporated into complete welfare measures. RESULTS: Resulting analysis, fully developed in an Appendix in Supplemental Materials found at https://doi.org/10.1016/j.jval.2024.02.005 and summarized in the main text, show that understanding how average and marginal healthcare costs increase with output and how health augments "additional values" provides ways to assess willingness to pay for them in these fixed-budget situations. CONCLUSIONS: In budget-constrained healthcare systems, only from actual budget allocations can values both of health itself and "additional values" be inferred. These methods, combined with methodologically sound social welfare functions, demonstrate how to move from "health" to "welfare" in measuring the value of increased healthcare use.

Three Pillars of Support for Orphan Drug Programs: Individual Valuations, Societal Valuations, and Anonymous Altruism.

OBJECTIVES: To identify and describe potential societal and individual sources of support for orphan drug programs. METHODS: The Generalized Risk-Adjusted Cost-Effectiveness method shows that acute illness and disability severity increase individuals' willingness to pay for health gains. We develop a social welfare function (SWF) that incorporates individuals' own values, combined with politically or ethically determined weights. We introduce the concept of horizontal equity-that individuals in similar situations should be treated similarly-into the SWF. Finally, we introduce anonymous altruism into individuals' utility functions-the desire to help others, without knowing their identity. RESULTS: Combined with the empirical link between disease severity and rarity, the Generalized Risk-Adjusted Cost-Effectiveness method demonstrates heightened willingness to pay for health gains for people with rare diseases, leading rational individuals to support orphan drug programs, our first pillar of support. Adding horizontal equity to the SWF further increases societal support for orphan drug programs. Anonymous altruism, focusing most strongly on those in the most-dire circumstances, leads to altruistic support for those with severe disorders. Because innovators' economic incentives lead them to focus on larger markets, anonymous altruistic individuals will increasingly prefer public investments into rare diseases over time, as private markets systematically produce gains for common diseases. CONCLUSIONS: We identified 3 supporting pillars for orphan drug programs: (1) individuals' propensity to prefer treatments for severe diseases; (2) the preference for horizontal equity in our social welfare; (3) anonymous altruism, the desire to help strangers, coupled with market incentives that underserve strangers with rare diseases.

Daily crowding stress has limited, yet detectable effects on skin and head kidney gene expression in surgically tagged atlantic salmon (Salmo salar).

To ensure welfare-friendly and effective internal tagging, the tagging process should not cause a long-term burden on individuals given that tagged fish serve as representatives for the entire population in telemetry applications. To some extent, stress is inevitable within regular aquaculture practices, and thus, the consequences of long-term stress should be described in terms of their effects on internal tagging. In fish, stressors activate the Hypothalamus-Pituitary-Interrenal (HPI) and Brain-Sympathetic-Chromaffin Cell (BSC) axes, leading to neuroimmunoendocrine communication and paracrine interactions among stress hormones. The interrelation between wound healing and stress is complex, owing to their shared components, pathways, and energy demands. This study assessed 14 genes (mmp9, mmp13, il-2, il-4, il-8a, il-10, il-12, il-17d, il-1b, tnfa, ifng, leg-3, igm, and crh) in the skin (1.5 cm from the wound) and head kidney over eight weeks. These genes, associated with cell signaling in immunity, wound healing, and stress, have previously been identified as influenced and regulated by these processes. Half of a group of Atlantic salmon (n = 90) with surgically implanted dummy smart-tags were exposed to daily crowding stress. The goal was to investigate how this gene panel responds to a wound alone and then to the combined effects of wounding and daily crowding stress. Our observations indicate that chronic stress impacts inflammation and impedes wound healing, as seen through the expression of matrix metalloproteinases genes in the skin but not in the head kidney. This difference is likely due to the ongoing internal wound repair, in contrast to the externally healed wound incision. Cytokine expression, when significant in the skin, was mainly downregulated in both treatments compared to control values, particularly in the study's first half. Conversely, the head kidney showed initial cytokine downregulation followed by upregulation. Across all weeks observed and combining both tissues, the significantly expressed gene differences were 12 % between the Wound and Stress+ groups, 28 % between Wound and Control, and 25 % between Stress+ and Control. Despite significant fluctuations in cytokines, sustained variations across multiple weeks are only evident in a few select genes. Furthermore, Stress+ individuals demonstrated the most cytokine correlations within the head kidney, which may suggest that chronic stress affects cytokine expression. This investigation unveils that the presence of stress and prolonged activation of the HPI axis in an eight weeklong study has limited yet detectable effects on the selected gene expression within immunity, wound healing, and stress, with notable tissue-specific differences.

Comparative Impact of Various Fasting Periods on the Welfare of Sprague-Dawley Rats With or Without Supplementation.

In nonclinical toxicology studies, lab animals are fasted typically overnight, to reduce variability in some clinical pathology parameters. However, fasting adds undue stress, and this is particularly concerning in rodents given their fast metabolic rates. Furthermore, as rodents are nocturnal animals, an overnight fasting may cause a protracted negative metabolic state even when the fasting has technically ended, given their minimal activity and food consumption during the day. Therefore, to evaluate the impacts of different fasting durations (±DietGel supplementation) on rats' welfare, we assessed the traditional and ancillary clinical pathology parameters in Sprague-Dawley rats, along with body weight, organ weight, and histopathology. Although most endpoints were comparable between the different fasting durations (±DietGel supplementation), the long fasting times (≥8 hr) without DietGel supplementation caused significant decreases in body weight, liver weight, liver glycogen content, serum glucose, triglyceride, and creatinine concentrations-all findings suggestive of a negative energy balance that could impact animal welfare and consequently, data quality; while the short fasting time (4 hr) and DietGel supplementation were associated with higher triglycerides variability. Hence, we propose that short fasting time should be adequate for most toxicology studies in rats, and long fasting times should only be accommodated with scientific justification.

Characterizing Multisystem Barriers to Women's Residential SUD Treatment: A Multisite Qualitative Analysis in Los Angeles.

Residential substance use disorder (SUD) treatment programs are challenged by the differing values of the problem-solving court (PSC) and child welfare (CW) systems, along with communication barriers between staff. This study aimed to understand, from the viewpoints of SUD treatment providers, how divergent values and communication barriers adversely affect women's residential SUD treatment. We conducted qualitative semistructured interviews with 18 SUD treatment clinicians and six directors from four women's residential SUD treatment programs. Using a thematic analysis framework, we identified salient themes across specified codes. Analysis revealed six main themes, suggesting differing values and communication barriers across the SUD, PSC, and CW systems adversely affect the provision of SUD treatment. For differing values, three main themes emerged: (a) unaddressed trauma and fear of mental health treatment seeking; (b) perceptions of mothers with a SUD; and (c) the Adoption and Safe Families Act (ASFA) timeline as a barrier to SUD treatment provision. For communication barriers, three themes emerged: (a) inadequate communication and responsiveness with PSC and CW systems adversely affect treatment coordination, induce patient stress, and treatment disengagement; (b) lack of PSC and CW communication regarding child visitation planning adversely affects treatment motivation and retention; and (c) competing ASFA, PSC, and CW priorities and inadequate cross-system communication adversely affect treatment planning. Treatment providers face significant barriers in providing effective treatment to women simultaneously involved in the CW and PSC systems. Aligning values and addressing communication barriers, changes in policy, and enhanced cross-system training are crucial. Additionally, it is essential to reevaluate the ASFA timeline to align with the long-term treatment needs of mothers with a SUD. Further research should explore the viewpoints of patients, CW, and PSC staff to gain deeper insights into these SUD treatment barriers.

Naturally acquired immunity to Plasmodium pitheci in Bornean orangutans (Pongo pygmaeus).

Naturally acquired immunity to the different types of malaria in humans occurs in areas of endemic transmission and results in asymptomatic infection of peripheral blood. The current study examined the possibility of naturally acquired immunity in Bornean orangutans, Pongo pygmaeus, exposed to endemic Plasmodium pitheci malaria. A total of 2140 peripheral blood samples were collected between January 2017 and December 2022 from a cohort of 135 orangutans housed at a natural forested Rescue and Rehabilitation Centre in West Kalimantan, Indonesia. Each individual was observed for an average of 4.3 years during the study period. Blood samples were examined by microscopy and polymerase chain reaction for the presence of plasmodial parasites. Infection rates and parasitaemia levels were measured among age groups and all 20 documented clinical malaria cases were reviewed to estimate the incidence of illness and risk ratios among age groups. A case group of all 17 individuals that had experienced clinical malaria and a control group of 34 individuals having an event of >2000 parasites µL−1 blood but with no outward or clinical sign of illness were studied. Immature orangutans had higher-grade and more frequent parasitaemia events, but mature individuals were more likely to suffer from clinical malaria than juveniles. The case orangutans having patent clinical malaria were 256 times more likely to have had no parasitaemia event in the prior year relative to asymptomatic control orangutans. The findings are consistent with rapidly acquired immunity to P. pitheci illness among orangutans that wanes without re-exposure to the pathogen.

The Legality of Labor and Perceptions of Deservingness of Rights and Services for Sex Workers.

Access to social services like healthcare, education, housing, and welfare are integral to creating an equitable society. While many populations inherently benefit from these services, sex workers are often denied these rights and services because of the nature of their work. The purpose of this study was to examine perceptions of deservingness of sex workers for a wide range of rights and services. This study distinguished those attitudes across legal and illegal forms of sex work, identified attitudinal and demographic correlates associated with those perceptions, and examined potential interactions between respondents' gender and age. Participants included a nationwide sample of adults from the USA (n = 549). Results indicated that participants perceived legal sex work as more deserving of rights and services compared to illegal sex work. Perceptions of deservingness were associated with attitudes toward abortion, LGBTQ+ rights, and perceptions of government legitimacy. Overall, older individuals were less willing to extend rights and services to sex workers and women were more likely to perceive sex workers as deserving of rights and services. There was an interaction between gender and age. For illegal sex work, gender differences in perceptions converged as participants aged, whereas for legal sex work, gender differences were exacerbated with age, with men reporting particularly restrictive perceptions of deservingness.

Partially divided caging reduces overall aggression and anxiety which may indicate improved welfare in group housed male C57BL/6J mice.

Deciding which environmental enrichment is used in mouse caging is often subjective, with cost frequently prevailing over welfare benefits, including aggression and anxiety. While many devices introduced to encourage natural behaviors and reduce aggression show mixed results, we have previously demonstrated significant reductions in aggressive behavior between group-housed male mice housed in partially divided caging. To further assess behavior, we have raised male C57BL/6J mice in either partially divided caging or in standard caging with no divider. Animal behavior was tested on rotarod, open field, novel object recognition, elevated plus maze, and Y maze. Body weights were taken weekly beginning at weaning and bite wounds were counted weekly beginning at 133 days old. Aggressive behavior was recorded weekly beginning at 133 days old. Results indicated significantly less anxiety in the elevated-plus maze, statistically fewer bite wounds, and a statistically significant decrease in aggressive behaviors of mice in partially divided caging compared to mice in standard cages. We conclude that reductions in anxiety, aggressive behavior, and bite wounds may indicate improved overall welfare for non-sibling, group housed male mice.

Effect of different LED light colors on welfare, performance, some behavioral patterns, and blood parameters of Muscovy ducks.

BACKGROUND: The current study was conducted to assess the impact of different LED light colors on welfare indicators in Muscovy ducks. These welfare parameters encompassed growth performance, specific behaviors, tonic immobility (TI), feather score, haematological, and serum biochemical parameters. Eighty-four healthy unsexed Muscovy ducklings aged two weeks were randomly assigned to four groups (3replicates/group; each replicate contains 7 birds) based on different LED light colors. The first group was raised under white light, the second under red light, the third under blue light, and the fourth under yellow light. To assess the impact of various LED light colors on welfare, growth performance indicators (body weight, body weight gain, feed intake, and feed conversion ratio) were measured. Behavioral patterns including feeding, drinking, standing, walking, sitting, feather pecking, and other activities were recorded. Tonic immobility test (TI) and feather condition scoring were conducted at 3, 6, and 10 weeks of age. At the end of the study blood samples were collected for hematological and serum biochemical analyses. RESULTS: The results revealed that using blue, yellow, and red colors had no adverse effect on the final body weight of the ducks (P > 0.05). Unlike to red light, blue light significantly reduced feather pecking, TI time and cortisol concentrations and improved the feather condition score (P ≤ 0.05). CONCLUSIONS: The current findings suggest that the application of blue light effectively improves welfare indices and has no detrimental impact on the growth performance of Muscovy ducks thereby positively contributing to their welfare.