The successful survival of crocodilian hatchlings is largely dependent upon nest care by females. Nonetheless, it is crucial to understand how environmental degradation affects nest site selection and parental behaviour in female crocodilians. Therefore, our objective was to evaluate the relationship between anthropogenic disturbances and nesting behaviour in free-living broad-snouted caiman (Caiman latirostris). We compared nests in a disturbed and a non-disturbed area, and anticipated differences in nest density, hatching success, female size, egg number and biomass, and parental care behaviour. We monitored 44 nests over four years in Brazil, covering 58.25 km, in a disturbed area (n = 8) and a non-disturbed area (n = 36). According to our findings, nest density was significantly higher in the non-disturbed area (1.31 nests per linear km) compared to the disturbed area (0.25 nests per linear km). However, there was a significantly higher frequency of parental care behaviour (86%) in the disturbed area compared to the non-disturbed area (34%). The other factors studied showed no statistical difference between the two areas. The results indicate that females prefer to nest in healthier, preserved environments, away from anthropogenic disturbances. Yet, presumably at the cost of extra energy expenditure, increased parental care appears to buffer against a reduction in hatching success. Despite the behavioural buffer, the clear preference for non-disturbed nesting and nursery locations underscores the need to identify and protect the remaining non-disturbed areas inhabited by these animals. Our findings suggest that these measures should positively impact the welfare and protection of C. latirostris and other crocodilian species.

Decapod crustaceans, commonly utilised for pure or applied scientific research and commercial food production, have generally remained outside ethical debate. However, in the last decade many parts of the world have seen an increase in public interest in the welfare of decapod crustaceans and statutory legal protection has been introduced in several countries. Although still limited to a small number of countries and remaining relatively unharmonised, relevant legislation could be increasingly broadened to include decapods in further jurisdictions. Much existing legislation, originally intended for protecting terrestrial vertebrates during scientific study, might be unsuitable for aquatic invertebrates such as decapods. Indeed, precedence with many fish species and cephalopods suggests detail is lacking with respect to fundamental guidance. Therefore, similar inclusion of decapods into such legislation could make welfare or scientific goals more challenging to achieve unless relevant guidance is available, particularly to animal care practitioners. This horizon paper aims to summarise existing decapod legislation, and the considerations required should decapods be included in current conceptual frameworks and scientific legislation.

Parrots (Psittaciformes) are widely kept in captivity, yet their welfare is under-researched in comparison to other captive species. This study aimed to determine key welfare issues affecting parrots through a modified Delphi approach. Twenty-eight welfare issues were first compiled via a preliminary literature review. Parrot welfare experts and sector professionals (n = 26) were then recruited to participate in an online survey to rank the identified welfare issues on a six-point scale according to severity, duration and prevalence of each issue. Participants could provide commentary on their ranking and propose additional welfare issues of concern. Items with a mean score of 4 or above progressed to a second survey, where participants (n = 14) indicated whether they agreed or disagreed with the current ranking of the welfare issue. Finally, two online workshops were held, where participants (n = 7) discussed the rankings from the second survey and sought to establish a consensus on the top ten welfare issues in each category and overall. Six of the seven final participants agreed with the final rankings, achieving a consensus rate of 86%. The top welfare issues overall were lack of owner knowledge and support; social isolation; housing; environmental opportunity to express behaviours; nutrition; development of normal behaviour; lack of a ‘life plan’ for birds; abnormal behaviours; lack of parrot-specific veterinary training; and insufficient application and enforcement of legislation. It is hoped that identification and recognition of these priority areas will be useful in directing future efforts in research, owner and veterinary education, and policy initiatives to improve parrot welfare.

Finding effective ways to monitor laying hen welfare is challenging as UK flock sizes can reach 16,000 birds. Eggs provide potential for welfare monitoring, as they are a daily output with previous evidence of links to stress. We explored the associations between stressors and eggs using two complementary studies. In Study 1, hens experienced social or heat stressors and eggs were scored daily for defects in shell characteristics. All eggs were scored on a three-point scale: 1 (no defect); 2 (minor defects); or 3 (unsuitable for whole egg sale in the UK). Texture defects were higher after stress treatments and were explored further as a promising proxy measure of welfare. In Study 2, eggshell texture from five commercial flocks was scored before versus at the onset of an avian influenza-enforced indoor housing, and scores were correlated with industry data for egg quality. Eggs were more likely to have texture defects after the enforced indoor housing, and manually scored texture correlated significantly with shell strength and shell colour during automated grading. Shell strength was weaker immediately after the enforced indoor housing and eggs were darker. We suggest that eggshell texture could be a useful addition to assessing changes or stresses in a hen’s environment for both research and commercial purposes, but further validation is needed to understand the generalisability of these results to other stressors. Additionally, data already collected in factories, such as shell strength and colour, may provide information on stress and could be valorised for understanding hen welfare.

Many companion kittens entering shelters are fostered by volunteer community members during the sensitive period for socialisation (~2 to 9 weeks of age) when early experiences are critical to behavioural development. Using a mixed-method survey, we explored current fostering practices relevant to kitten behavioural development and welfare. Foster caretaker participants (n = 487) described their fostering practices and reported providing kittens with a majority of recommended socialisation experiences, such as handling and exposure to various toys and exploratory items. In open-ended text responses, foster caretakers described how they adapted socialisation practices for fearful kittens and the supports and challenges they perceived to impact their ability to properly socialise kittens. Some non-recommended techniques (e.g. flooding) were reported for socialising fearful kittens, with a decreased odds of reporting non-recommended techniques for participants with a higher level of agreeableness personality trait and an increased odds of reporting if fostering practices had been impacted by the COVID-19 pandemic. Foster caretakers reported feeling supported through shelter-supplied resources, personal knowledge, external support, and having access to socialisation opportunities; however, faced personal (e.g. time constraints), shelter-specific (e.g. lack of shelter support), and kitten-specific challenges (e.g. kitten illness). This study highlights the perspectives of foster caretakers as related to optimal socialisation, behavioural development, and welfare. To identify opportunities for improvement it is important to investigate the socialisation guidelines provided to foster caretakers, with the ultimate goal of enhancing kitten behavioural development for improved welfare, long-term adoption, and caretaker satisfaction.

Behavioural complexity is likely to reflect how animals cope with their environment. A large behavioural repertoire and the ability to flexibly apply these behaviours provide an individual with a greater likelihood of adapting to its (captive) environment. Here, we developed a procedure to aggregate different behavioural measures into a condensed measure of behavioural complexity based on 14 features, which were previously proposed (e.g. number of behaviours, Shannon diversity index) as well as some new features of behavioural complexity (e.g. variances of within and between transition durations). To test the measure, artificial behavioural sequences with potentially varying complexity were created using an individual-based modelling approach. With a Principal Component Analysis, the features extracted from these sequences could be reduced to two components (‘general complexity’ and ‘state variability’) explaining 59.64 and 27.68% of the total variance, respectively. The effect of the aspects of the artificial behavioural sequences on ‘general complexity’ and ‘transitions variability’ were analysed using linear mixed-effects models. The number of behavioural categories and the proportion of short behavioural states had the largest effect on the components. Both components were increasing with a greater number of behavioural categories, whereas the proportion of short behavioural states the opposite effect on the components. We also tested the approach on real data-sets. The principle components were not identical to the ones from the simulation. Yet, we found consistencies and similarities in the loadings. The approach for an aggregated measure of behavioural complexity developed here could form the basis of an individual-based animal welfare indicator for intensively kept animals.

Horses employ a range of subtle to overt behaviours to communicate their current affective state. Humans who are more cognisant of their own bodily sensations may be more attuned to recognising affective states in horses (Equus caballus) thereby promoting positive human-horse interactions. This study investigated human ability to categorise human-horse interactions depicted in media relative to equine behaviour experts and compared participant scores to their level of interoception. Using an online survey, participants (n = 534) categorised 31 photographs and videos as (overt) positive, likely (subtle) positive, neutral, likely (subtle) negative or (overt) negative human-horse interactions from the horse’s point of view and completed the Multidimensional Assessment of Interoceptive Awareness questionnaire (MAIA-2) to assess their level of interoception. Demographic information was also collected (age, gender, education, level of experience with horses, location). Participants differed from expert categorisations of horse affective states across all categories, exactly matching experts only 52.5% of the time and approximately matching experts for positive and negative valence 78.5% of the time. The MAIA-2 did not predict participant ability to accurately categorise human-horse interactions. Women outperformed men in categorising overt positive, overt negative and subtle negative human-horse interactions. Increased levels of education and greater experience with horses were associated with improved categorisation of certain human-horse interactions. More training or awareness is needed to recognise behavioural indicators of horse affect to guide appropriate human-horse activities that impact horse welfare.

The activity level and specific behaviours exhibited by captive animals are crucial indicators of welfare. Stereotypies, or repetitive behaviours that have no apparent function or goal, are performed by animals experiencing poor conditions in their environment and indicate welfare concerns. Changes in the housing environment in particular may have critical influences on behaviour and welfare. Here, we measured behavioural changes in a captive pinyon jay (Gymnorhinus cyanocephalus) population (n = 10) associated with a shift from single to pair housing. Using automated video processing, we show that pair housing greatly reduced overall activity levels in these birds. The stark reduction in activity was surprising, as we expected that social housing would increase interactions between birds, thus increasing activity levels. Upon further analysis, however, we found that stereotypic behaviours, such as beak scraping, jumping, pecking, and route tracing decreased after pair housing, whereas the positive welfare behaviours of perching and preening increased. Our results indicate that pair housing may reduce overall activity in pinyon jays; however, this reduction is primarily in stereotypic behaviours.

Both the nature of the human-animal relationship (HAR) and housing conditions significantly impact the welfare of farmed animals. To evaluate the influence of HAR on the behaviour, emotions and stress of rabbits (Oryctolagus cuniculus) in two distinct outdoor living environments, we allocated 144 young rabbits to four groups (CPX-H, CPX-N, SPL-H, SPL-N) differing in the living environments (CPX for complex, and SPL for simple). The treatment by human (H) involved daily provision of additional food resources and stroking (thoughtful farmer). It commenced at 49 days of age and lasted for 16 days. N groups did not receive the treatment (distant farmer). The rabbits were observed between 48 and 73 days of age. Their behavioural responses to human presence were evaluated at 48 and 68 days using Qualitative Behaviour Assessment (QBA) and scan sampling. A set of tests was conducted at 68 days of age to assess their reactions to a novel object and human presence. Stress levels were measured by analysing corticosterone concentrations in their hair. Rabbits in the SPL environment spent significantly more time near the novel object than those in the CPX environment (24.7 vs 17.2%). Additionally, rabbits in the H treatment group spent more time near the human than those in the N treatment group (28.2 vs 17.1%) and accepted more strokes (90.2 vs 45.9%). Following the HAR treatment, rabbits in the H group were significantly more likely to be described as ‘Affectionate/Interested’ than those in the N treatment. Rabbits in the N treatment were described as ‘Indifferent’ significantly more in the SPL environment. However, there were no significant differences in hair corticosterone concentrations between the groups. These findings indicate that rabbits’ responses are influenced by both their living environment and the quality of their relationship with humans. Encouraging positive interactions with animals may enhance their welfare and facilitate daily care from farmers.

In-farm livestock production vaccinations are commonly delivered intramuscularly using needles. While there are alternative strategies these have been subject to little attention and limited commercialisation. One such alternative is needle-free vaccines and studies have focused on the immune response few have addressed the welfare implications. This study aims to compare the impact of intradermal needle-free vaccination and intramuscular injection in terms of the welfare of the piglets. A total of 179 piglets were divided into two treatments: intradermal needle-free delivery and intramuscular delivery of a vaccine. Measures of health and welfare included, vocalisations, behavioural observations, papule formation, and weight. Piglets vaccinated via the needle-free intradermal route vocalised less and displayed no significant behavioural differences but showed increased weight compared to piglets vaccinated intramuscularly. The use of a needle-free device to deliver a vaccine through an intradermal route revealed no adverse effects on piglet welfare and supports the use of alternative strategies to vaccinate livestock.

Pain, a multifaceted condition associated with actual or potential tissue damage, transcends nociception and is characterised as a subjective, sensory, and emotional experience. Extensive literature describing the adverse effects of untreated post-surgical pain emphasises the necessity of a comprehensive pain management protocol, incorporating both pharmacological and non-pharmacological strategies to ensure successful patient outcomes. The present study aimed to determine whether a positive dog-owner interaction influences post-operative pain perception and stress (POPPS), as well as behavioural inactive rate variability in bitches that underwent elective surgery. Randomly selected bitches (n = 18) underwent ovariohysterectomy. Eight bitches experienced a 45-min visit post-surgery (VPS) characterised by positive dog-owner interaction, while the remaining ten did not (NVPS). Utilising the validated Short Form of the Glasgow Composite Measure Pain Scale (CMPS-SF) to assess acute pain in dogs via stress-related behaviours, a significant decrease in POPPS was evident in the VPS group after the 45-min dog-owner interaction at T3 (1 h after post-sedation recovery), in contrast to the NVPS group. CMPS-SF-associated descriptive items ‘Nervous/Anxious/Fearful’ and ‘Happy Content or Happy and Bouncy’ decreased and increased, respectively, with dog-owner positive interaction in the VPS group. The inactivity rate was significantly lower in VPS bitches after the post-surgery 45-min dog-owner interaction than in NVPS bitches. This preliminary study suggests that the owner’s presence reduces POPPS and may improve the dogs’ welfare while undergoing routine surgeries.

The emotional valence hypothesis suggests an increased left-brain hemisphere activation during positive situations and vice versa during negative situations. Since facial thermal asymmetries may reflect lateralised brain activity, we investigated this in dairy calves subjected to hot-iron disbudding (Disbudded; n = 12) as a model of negative affective states. As affective responses can vary due to previous experiences, we examined whether calves that had (ExpObs; n = 12) and had not (InexObs; n = 12) experienced disbudding differed in their thermal response to a conspecific being disbudded, and whether calf response to the researcher (approaching, moving away, not moving) was associated with thermal asymmetries. We made thermographic recordings of each calf on three days: Day before disbudding (D1); Disbudding day (D2); and Day after disbudding (D3), and at two different times: Disbudding time/1400(T1) and Afternoon/1700(T2). Data were analysed using multilevel models. Calves had warmer left ears on D2 compared to higher temperatures on the right ear on D1, suggesting higher right-hemisphere activity on D2. ExpObs calves had higher left-eye temperatures when observing a conspecific being disbudded (D2×T1) than InexObs calves that had warmer right eyes, but this reversed on the following day (D3×T1). Calves avoiding the researcher had warmer left eyes whereas those approaching him had warmer right eyes, suggesting greater activation of the right hemisphere in the former. This study provides initial evidence of temperature asymmetries when observing or experiencing a negative event. Further work is required to confirm and build upon these early findings. The study highlights the potential for future development of methods using infrared thermography as a proxy measure of affective valence.

Post-racing thoroughbreds (TBs) are increasingly being considered for Equine Assisted Services (EAS), but their use has not yet been widely characterised. This study aimed to generate detailed data on TBs and other breeds (OBs) of horses in EAS via an online survey. The survey was completed by 129 EAS practitioners from 15 countries and reported detailed data on 427 EAS equids, including 57 TBs. Most of the EAS horses were housed collectively, had access to free exercise over 12 h per day and had unrestricted access to forage. The most commonly recorded selection criteria for EAS horses consisted of: demonstrating a good personality; enjoying the work; absence of propensity to kick/bite. Detailed data gathered on individual horses showed that in comparison to OBs, TBs were younger, more likely to be a gelding, less likely to be used in ridden programmes, and tended to present more behavioural issues than OBs. The majority of the participants agreed that TBs have specific assets of particular interest to EAS programmes, such as sensitivity, body/movement characteristics or responsiveness/flight response. Finally, a large majority of participants reported that they believe TBs to be suitable for EAS programmes and some would consider working with them. These results showed TBs to already be in use in various EAS programmes and more could be incorporated in the future. In terms of animal welfare and beneficiaries’ safety, a selection process could therefore be designed and implemented to choose the most adapted horses for each EAS centre, according to living conditions and EAS activities practised (ridden or not ridden).

Signs of distress in dogs during veterinary visits are often normalised rather than viewed as welfare concerns. Interventions designed to reduce fear during veterinary visits were evaluated to see if they affected dogs’ behaviours compared to dogs without interventions. Twenty-eight dogs were examined at four visits across eight weeks. Dogs were randomised into intervention (distress reduction/adaptive care) and control groups (standard care) and evaluated via the Working Dog Questionnaire – Pet Dog Version (WDQ-Pet). At visit 1 (baseline) all dogs received the control protocol. Homework was assigned following visit 1 to practice collaborative examination (intervention) or to pet the dog (control) for the same allotted time. At each visit, behaviours were scored (clinical stress score) via video and in-person observations when dogs entered the hospital, stepped onto a scale to be weighed, entered the exam room, at the beginning and end of examination, and after venipuncture. There were no differences between groups at visit 1, or across visits entering the hospital or exam room. At visit 4, intervention scores either decreased or remained low when weighed, and at the beginning and end of the physical exam. Control scores were significantly higher than the intervention scores during these periods. Reduced clinical stress scores indicate intervention dogs had improved care experience compared to the control. The study results highlight the value of applying simple and adaptable interventions, ultimately leading to improved animal care and welfare.

Working equids support the livelihoods of millions of low-income households worldwide and face several welfare challenges. Although equipment-related wounds are common, little is known about specific risk factors. This cross-sectional study surveyed equids used for cart-work in three Ethiopian towns. Number, size, severity and location of wounds were recorded for each animal, as well as work equipment characteristics and indicators of equipment fit and assembly. Questionnaires were conducted with each cart-driver focusing on equipment practices and attitudes. Logistic regression models were generated to investigate associations between equipment-related wounds (outcome) and equipment, work, driver and animal-related factors (predictors). In total, 369 equids and cart-drivers were surveyed. The prevalence of equipment-related wounds was 72.6% (268/369) with girth wounds being the predominant wound type in horses (50%; 122/244) while donkeys had predominantly shaft-related wounds (59%; 72/122). Donkeys were two times more likely to have equipment-related wounds than horses. The presence of equipment-related wounds was associated with factors such as previously having wounds, inadequate collar positioning and using purchased equipment compared to partly home-made equipment. Characteristics of specific equipment components were also associated with certain wound types, such as narrow saddle pressure points and saddle wounds. Equipment-related wounds are highly prevalent in working equids, representing a serious welfare concern. Factors relating to equipment design, fit and assembly were associated with the presence of wounds. Importantly, species differences require tailoring of preventive approaches amongst working equids. A better understanding of work equipment should therefore be promoted as part of wound prevention and animal welfare strategies.

The welfare of horses involved in sport and leisure activities has come under increasing scrutiny, both from within the equine sector and from the public. A systematic review of scientific evidence was conducted to derive observable, evidence-based behavioural measures of positive or negative affective state and factors relating to quality of life in the domestic horse (Equus caballus). Two separate searches (including the terms ‘emotion/affect’, or ‘stress’) were conducted, with 179 articles being retained. In Part I of this two-part review (companion paper published simultaneously), articles relating to the extent to which the species-specific needs of the horse are fulfilled in the home environment (n = 21), in relation to social grouping (n = 20), and during weaning (n = 14) were reviewed. Experimental tests of affective state in relation to housing and management (n = 8), and studies relating to stereotypical behaviour (n = 7) were also included. Opportunities for behavioural expression were dependent upon the provision of social and physical resources. Withdrawn or agitated behaviours in situ, avoidance behaviour during handling and agonistic intra-species interactions were indicative of negative affective state. Affiliative intra-specific social interactions, and forage ingestion were considered positive signs. For horses to live a good life, their need for space, companionship, and forage must be prioritised from birth and throughout their lives.

Quality of life is dependent upon the extent to which behavioural needs are met, and the balance between pleasant and unpleasant lifetime experiences. In Part II of this systematic review, articles (n = 109) relating to horse-human interactions were reviewed to identify behavioural evidence of their positive or negative impact on the horse. The number of articles (n = 22) relating to the recognition of pain in horses, indicated the importance of identifying health issues, which are also likely to increase the aversiveness of interactions. These and articles relating to emotional reactivity testing in horses (n = 19), the behaviour of horses during handling and management procedures (n = 17), behaviour of the horse when ridden (n = 17), non-procedural horse-human interactions (n = 13), horse behaviour during transportation (n = 12) and behaviour during training other than when ridden (n = 9) were reviewed. During most interactions, horse behaviour is controlled and/or restricted by the human, masking negative or positive signs, and may be confounded by factors including fear and individual differences. In situations involving freedom of movement, positive experiences of horses with humans were associated with approach behaviour, negative ones with avoidance, but training could affect both. Undoubtedly, change is needed to reduce the extent to which interactions with humans are unpleasant for the horse. Only when the needs of the horse are fulfilled and interactions with humans are predominantly pleasurable will their quality of life improve.

According to the Bayesian brain hypothesis, the brain can be viewed as a predictive machine, such that predictions (or expectations) affect how sensory inputs are integrated. This means that in many cases, affective responses may depend more on the subject’s perception of the experience (driven by expectations built on past experiences) rather than on the situation itself. Little research to date has applied this concept to affective states in animals. The aim of this paper is to explore how the Bayesian brain hypothesis can be used to understand the affective experiences of animals and to develop a basis for novel predictions regarding animal welfare. Drawing from the literature illustrating how predictive processes are important to human well-being, and are often impaired in affective disorders, we explore whether the Bayesian brain theories may help understanding animals’ affective responses and whether deficits in predictive processes may lead to previously unconsidered welfare consequences. We conclude that considering animals as predictive entities can improve our understanding of their affective responses, with implications for basic research and for how to provide animals a better life.

A wide range of animal taxa, including vertebrates and invertebrates, are controlled or kept by humans. They may be used as pets, for recreation, sport and hobbies, as working animals, as producers of animal-derived (food) products or as biomedical models in research. There is a need for clear guidance on the treatment of animals, regardless of their phylogenetic distance from humans. Current animal welfare concepts, which emphasise animal sentience and the ability of animals to experience negative or positive mental states, are limited in scope to a small proportion of the animal kingdom, as the vast majority of species are (currently) thought to lack sentience. We discuss four options for addressing the question of which basic concept(s) could be used to derive guidelines for the treatment of animal species, sentient or non-sentient: (1) alternative concepts tailored to specific groups of species; (2) ‘welfare’ concepts not presupposing sentience; (3) the precautionary principle; or (4) the concept of animal integrity. Since questions regarding the appropriate treatment of animals, including species with a large phylogenetic distance from humans, have an ethical/moral dimension, we also address who counts morally and how much, and how animals should be treated given their moral status. We suggest that the concept of animal integrity, possibly complemented and extended by the concept of habitat/ecosystem integrity, is suitable for application to all species. However, a current concept of animal welfare should serve as the primary basis for guidance on how to treat species that are sentient and capable of experiencing emotions.

Russell and Burch’s 1959 original definitions of the 3Rs (replacement, reduction and refinement) are widely used today as standards for the ethical use of non-human animals in research, although they have a number of limitations. Authors and institutions around the world have addressed some of these, coming up in certain cases with more accurate, functional, and up-to-date definitions. However, not only do there still remain limitations needing to be addressed, but some that have been addressed resulted in discrepancies, contradictions, and general confusion as to how best apply the 3Rs in practice. In order to clarify the meaning of the 3Rs and enable more optimal implementation of these principles in animal experimentation, this article provides a theoretical discussion for revised definitions of the original 3Rs via examination of some of their main limitations and inconsistencies. First, we offer up the original definitions as presented in the context of Russell and Burch’s book The Principles of Humane Experimental Technique. Then, we examine the main limitations and present clear specifications and requirements for such revised definitions. After presenting our revised definitions, we conclude with various implications for animal welfare within the context of experimentation.