The aim of this study was to develop a set of tests to assess the reaction of laying hens towards humans in non-cage systems and to investigate the repeatability within and between days.

Based on a literature survey six tests were developed or modified, which were examined for practicability and adapted in a first phase. Reactions of hens were recorded directly or with a video camera. These included the reaction towards a stationary person: stockperson (SPs); experimenter: (SPe); a moving person: (moving through flock [MP]; approaching individual hens measuring avoidance distance [AD]) and a complex test including stationary and moving elements: (arm moving to touch hens [touch test] in the litter [Tl] and on the slatted area [Ts]). Six flocks of five farms were visited twice, one week apart. At each visit the six tests were performed during morning and afternoon hours. The order of the tests differed between farms.

Repeatability of flock reactions within as well as between days was high for SPs, AD and Tl. SPe and especially MP showed slightly reduced correlations. Touching hens at the droppings pit (Ts) was less repeatable than in the litter area (Tl).

To sum up, first experiences show that most tests can be practically used in groups of hens in non-cage systems and seem to have good repeatability.

Spatial restriction and low cage height can reduce the rate at which comfort activities, such as wing flaps, stretching, body shakes and tail wags, are carried out by laying hens in conventional wire cages. In this study we investigated the performance of these activities in laying hens housed in furnished cages with perches and nest boxes, similar to those required in EU legislation from 2012. We compared the behaviour of groups of eight hens at a stocking density of 762 cm2 per bird with that of pairs of hens housed at a lower stocking density of 3048 cm2 per bird at two minimum cage heights of 38 cm and 45 cm. The rates of wing/leg stretches (0.80 stretches per hen per hour), tail wagging (0.76), body shaking (0.48), wing raising (0.19) and feather raising (0.05) were low, whilst full wing flaps were not observed during the study. Hourly rates of performance of wing/leg stretches (0.45 vs 1.06) and tail wags (0.34 vs 1.25) were significantly lower in eight-bird cages than in two-bird cages. We conclude that reducing the number of hens in furnished cages increases opportunities to perform certain comfort activities, but that, even at low stocking densities, comfort activities are rarely observed.

Frequent diet change has been identified as a risk factor for feather pecking in commercial flocks but the mechanism underlying this association is not known. In this experiment we simulated a commercial change of diet between high quality (HQ) 19% protein, and low quality (LQ) 15% protein, diets. Twelve pairs of birds were fed both diets simultaneously for 38 days to determine whether clear preferences for the diets existed. A further 12 triplets of birds were fed either HQ or LQ diets for 38 days to examine any absolute effects of quality on behaviour. The remaining triplets received, on day 29, either a LQ to HQ diet change (n = 12 groups) or an HQ to LQ diet change (n = 12 groups). Half of the groups in these diet change treatments received oregano oil as a potential ‘masking’ agent to disguise the diet change. No dietary preferences were detected and there were no absolute effects of diet on behaviour. Diet change provoked significant increases in beak-related activity. Specifically, affiliative pecking (allopreening directed towards comb or beak) was increased after diet change. Masking the diet reduced the effects of diet change. Injurious pecking remained at low levels throughout the experiment and was not affected by diet change, but the relationship between affiliative pecking and subsequent injurious pecking requires further investigation.

The aim of this study was a comparison of Animal Needs Index (ANI) data, derived from annual inspections by a control agency, with data collected from 164 selected on-farm flocks concerning feather damage, injuries, egg production, mortality, bodyweight, foot pad dermatitis, keel bone deviations and reactions towards humans (eg flock showed marked avoidance when the observer walked through the hen-house [yes/no]).

Analysis of data showed a low number of significant correlations with total ANI scores and category scores: 1) Locomotion, 2) Social interaction, 3) Flooring, 4) Light, air and noise and 5) Stockmanship. Correlations found were low and total ANI score showed only a positive correlation with egg production at week 52. Category 3 scores correlated positively with egg production at week 70 and negatively with the percentage of hens with featherless areas and total pecking injuries. Category 5 scores showed positive correlations with egg production at week 52 as well as week 70 and negative correlations with mortality at week 52, the percentage of hens with featherless areas, pecking injuries < 0.5 cm and total pecking injuries.

Flocks showing marked avoidance had a lower total ANI score and lower category 3 and category 5 scores.

In conclusion, welfare-related animal-based parameters are poorly reflected by the ANI-35-L/2001. To assess animal welfare more adequately, animal-based parameters have to be considered additionally in a welfare assessment scheme.

Following the 2012 European ban (1999/74/EC) of conventional battery cages, only furnished cages will be allowed for laying hens. However, even when furnished cages provide a pecking and scratching area most dustbathing occurs on the wire floor. This study aimed to investigate whether laying hens showed a preference for dustbathing on a covered wire floor rather than a conventional wire floor. Eight groups of 10 hens were housed in pairs of adjoining furnished cages. All hens were leg-ringed for individual identification. Each pair of cages consisted of one cage containing a wire floor covered with perforated Astroturf and a second cage containing a conventional wire floor, joined by a pophole through which hens had unrestricted access. Initial scan samples were taken to investigate the general behaviour of the hens on each floor type. Dustbathing was observed more frequently on Astroturf and no other behaviours were affected by the floor type. Scans were subsequently taken at 5 min intervals between 1130h and 1600h for 10 days, identifying the number of hens, and which individual hens, were dustbathing on each floor type. Data were analysed on a per cage basis, using the binomial sign test. A strong preference was found for dustbathing on Astroturf flooring that was apparent in all cages. Furthermore, the distribution of hens indicated this was not attributable to any overall preference for either floor type but was specific to periods when hens were dustbathing. This demonstrates that there is the potential to include Astroturf in the design of furnished cages, as a dustbathing substrate, in order to improve the welfare of laying hens.

Six commercial hatcheries were visited in the United Kingdom, three of which processed laying hen chicks and three of which processed broiler chicks. The accelerations experienced by the chicks passing through the handling systems were evaluated using miniature data logging accelerometers, which were sent through the systems. The lengths, speeds, and heights of drops of the pathways within each system were also measured. The response of the chicks to the handling was measured in terms of mortality, orientation, righting time (as a measure of disorientation) and tonic immobility. The study showed there to be a range in the physical severity of handling across the hatcheries that could also be seen in terms of differences in the measurements made on the chicks. Nonetheless, the welfare of the chicks passing through the automated systems appeared to be generally acceptable. However, given the velocities and accelerations within these handling systems, there is scope for considerable damage to the chicks, and for poor welfare, if systems are not properly set up or maintained.

The integration of outcome-based measurements to animal welfare assessment programmes can provide a new perspective on the individual animal's experience. Identifying variability in individual experiences can facilitate understanding of animals at the periphery of the welfare spectrum, compared to those at the average. Welfare Quality® physical measurements and behavioural observations were taken from the same fifteen non-cage laying hens throughout their production cycle. The average amount of time performing each of nine behaviours and the amount of variation in each behaviour's performance was compared at four different ages: 19, 28, 48 and 66 weeks. The same analysis was performed for all Welfare Quality® physical measurements. To identify associations between a hen's behaviour and her physical condition, a cluster analysis was performed for all ages, as well as on data collated from all ages. No differences were observed among the four ages for the average amount of time performing many of the behaviours, but the amount of variability differed for most behaviours observed. Physical measurements taken at 19 weeks differed from those taken at later ages. Bodyweight consistently clustered with time spent preening, yet the patterns of clustering differed at each age. These results highlight the importance of age when conducting welfare assessments. Auditors also should report not only the average, but the variability of responses; while the average response of the flock may appear consistent across time or treatment, differences among the hens within the same flock may vary drastically.

The objective of this study was to investigate the effects of social rank (Experiment 1) and familiarity (Experiment 2) on dust-bathing in domestic hens (Gallus gallus domesticus). We conducted choice tests between two conditions using actual birds as the stimuli and evaluated the effects in terms of quality and quantity of dustbathing performed. Twenty-four, medium-ranked hens were selected as test subjects. The stimuli presented were combinations of a high-ranked hen, a low-ranked hen, or no hen at all for Experiment 1, and a combination of a familiar hen, an unfamiliar hen, or no hen for Experiment 2. The number and duration of dustbaths, wing tosses as well as other behaviours were measured. For Experiment 1, the test hen performed dustbathing more frequently on the side of the hen, regardless of its social rank, when presented with a choice of a high- or low-ranked hen, or no hen. For Experiment 2, the test hen performed dustbathing more frequently on the side of the familiar hen when presented with a familiar hen or no hen, and more frequently on the side of no hen when presented with an unfamiliar hen and no hen. It was concluded that dustbathing was not affected by social rank, and that the quality and quantity of dustbathing was greater on the side of the familiar hen. However, dustbathing was restricted by the presence of an unfamiliar hen.

Most farm assurance schemes in the UK at least, in part, aim to provide assurances to consumers and retailers of compliance with welfare standards. Inclusion of welfare outcome assessments into the relevant inspection procedures provides a mechanism to improve animal welfare within assurance schemes. In this study, taking laying hens as an example, we describe a process for dealing with the practical difficulties in achieving this in two UK schemes; Freedom Food and Soil Association. The key challenges arise from selecting the most appropriate measures, defining sampling strategies that are feasible and robust, ensuring assessors can deliver a consistent evaluation and establishing a mechanism to achieve positive change. After a consultation exercise and pilot study, five measures (feather cover, cleanliness, aggressive behaviour, management of sick or injured birds, and beak trimming) were included within the inspection procedures of the schemes. The chosen sampling strategy of assessing 50 birds without handling provided reasonable certainty at a scheme level but less certainty at an individual farm level. Despite the inherent limitations within a time and cost sensitive certification assessment, the approach adopted does provide a foundation for welfare improvement by being able to highlight areas of concern requiring attention, enabling schemes to promote the use of outcome scoring as a management tool, promoting the dissemination of relevant technical information in a timely manner and increasing the scrutiny of standards important for the welfare of the birds.

In Sweden, laying hens are killed using the following methods: i) traditional slaughter; ii) on-farm with CO2 in a mobile container combined with a grinder; or iii) with CO2 inside the barn. The number of hens killed using the latter method has increased. During these killings a veterinarian is required to be present and report to the Swedish Board of Agriculture. Data were registered during four commercial killings and extracted from all official veterinary reports at CO2 whole-house killings in 2008-2010. On-farm monitoring showed that temperature decreased greatly and with high variability. The time until birds became unconscious after coming into contact with the gas, based on time until loss of balance, was 3-5 min. Veterinary reports show that 1.5 million laying hens were killed, in 150 separate instances. The most common non-compliance with legislation was failure to notify the regional animal welfare authorities prior to the killings. Six out of 150 killings were defined as animal welfare failures, eg delivery of insufficient CO2 or failure to seal buildings to achieve adequate gas concentration. Eleven were either potentially or completely unacceptable from the perspective of animal welfare. We conclude that, on the whole, the CO2 whole-house gas killing of spent hens was carried out in accordance with the appropriate legislation. Death was achieved reliably. However, there remain several risks to animal welfare and increased knowledge would appear vital in order to limit mistakes related to miscalculations of house volume, improper sealing or premature ventilation turn-off.

People's awareness of livestock welfare has increased in recent years and veterinarians have a critical role to play in maintaining and improving these standards. The aim of this study was to explore the attitude of veterinary students to livestock welfare and an online questionnaire was utilised to gauge the opinions of students from the Bursa Uludag University Faculty of Veterinary Medicine in Turkey. A five-point Likert scale covered judgments ranging from ‘Strongly disagree’ to ‘Strongly agree.’ Female students were found to have a higher score for questions related to the welfare of livestock than males. It was also found that students yet to undertake courses in clinical science and animal welfare, ie first and second years, gave higher scores than third, fourth and fifth years who had completed both of these. Moreover, students having owned or dealt previously with livestock provided lower animal welfare scores than their counterparts who had done neither. Seemingly, the sensitivity of veterinary students decreases during the latter stages of their education. To conclude, we suggest further investigation into the extent to which veterinary medicine education influences students’ attitudes to animal welfare as they progress through the course.

A majority of laying hens fracture their keel bones during the laying cycle. It is not easy for a farmer to identify hens with fractures and hen survival rate seems high. Thus, the effect of both recent and healed fractures on bird welfare is unclear. We aimed to investigate the impact of these keel-bone fractures on hens’ production and behaviour. The egg production, mobility and behaviour of Lohmann Brown hens without keel fractures were compared with that of hens with old healed fractures of varying severity. In addition, the keel-bone strength and body temperature around the fracture site was measured for each group. Hens with no fractures laid more eggs and had a higher egg-quality score (derived from measures of egg weight, egg surface area, shell weight, shell percentage and shell density). These hens had the highest keel area temperature, strongest keel bones, accessed perches more frequently and took a shorter time to negotiate a walkway obstacle test and to fly down from a raised perch. Hens without keel fractures were better in all investigated parameters than hens with keel fractures, indicating a detrimental effect of fractures on both welfare and economic return.

The long-term effects of infra-red beak treatment (IRBT) in laying hens were investigated by examining beak-nerve function and anatomy over a range of ages. In IRBT and control (intact) birds that were ten, 30 or 50 weeks old, the responses of single sensory nerve fibres were recorded from the intramandibular nerve, which provides sensation to the lower beak. The beaks were also measured and subject to microscopic and radiographic examination. The responses of 386 nerve fibres were recorded including mechanoreceptors, thermoreceptors and nociceptors. Receptive field positions indicated that the entire lower beak was sensitive to thermal and mechanical stimuli, regardless of age or treatment. There was no evidence of a treatment effect on nociceptive thresholds at any age. Beak measurements demonstrated that application of IRBT at day-old affected, on average, 36% of beak area, and resulted in a 44% reduction in beak length by four weeks of age. Radiographs produced no evidence of adverse or pathological change in relation to IRBT. Microscopic evaluation of beak-tip anatomy revealed evidence of healing including re-epithelialisation, fibrovascular hyperplasia and bone remodelling. By four weeks of age there was limited nerve regeneration in IRBT beaks, including re-population of mechanoreceptors in some birds. In older birds, re-innervation and scarring was visible, but no neuromas or abnormal proliferations of nerve fibres were observed at any age. Collectively, the results suggest that IRBT does not result in chronic pain or other adverse consequences for sensory function.

The assessment of animal welfare requires the collection of multiple indicators of welfare but quantification of their associations in different contexts is lacking. Previous studies have examined correlations between a few indicators, but not relationships between many different indicators, or between indicators taken from the same individuals in more than one environment. We housed 60 hens for six sequential 35-day phases in different pen environments. During each phase, a series of behavioural and physiological measures was taken for every bird: body and plumage condition, surface body temperature, behaviours observed in the home pens and during test periods, tonic immobility, physiological blood profiles, and faecal sample composition. Most variation in nearly all measures was not explained by either individual bird or grouping effects but varied across phases within the birds. Acknowledging this, we examined correlations between all parameters at the phase within-bird level, selecting a conservative P-value. A consistent set of correlations showed that a slow approach response and alert behaviour in the novel object test was associated with higher bodyweight, lower body temperature and lower acute phase protein, heterophil: lymphocyte ratio and blood glucose level. A cluster analysis confirmed these correlations. Other important parameters known to be linked to the hens’ environmental preference (eg comfort behaviour) were independent of the set described above. We conclude that statistical techniques can reveal patterns of independence and redundancy in the collection of behavioural and physiological measures of welfare.

EU-Directive 1999/74/EC stipulates that furnished cages and non-cage systems for laying hens should be provided with perches. This Directive allows for a wide variety in perch design features possibly affecting perch use and hen health. Perch material and shape mainly affect slipperiness and grip quality and, in this regard, plastic, metal and circular perches are inferior. The incidence of bumble-foot and keel bone deformities can be influenced by perch shape. Perch shapes which reduce localised pressure on the foot pad and the keel-bone are recommended. Several aspects of the arrangement of the perches in the cage or non-cage system are also important. A consistent preference for high perches is seen, provided there is a minimal distance of 19–24 cm between perch and roof. Accessibility of high perches should be ensured, for example by incorporating lower level perches from which hens can reach the higher levels. Such multi-height perch designs also allow behavioural differentiation according to perch height (with most passive behaviour on the higher perches). In non-cage systems, good accessibility can be achieved by minimising the angles between perches at different heights to smaller than 45° and by limiting the distance between horizontal perches to 1 m. The legislated minimum perch length provided per hen (15 cm) adequately allows for synchronised roosting behaviour on straight perches. However, in crosswise perch designs, hens require more perch length per hen as the area close to the cross cannot be used optimally.

The outdoor range in free-range, egg-production systems contains features that aim to promote the performance of natural behaviours. It is unclear what features of the range laying hens prefer and how these influence hen behaviour. We hypothesised that hens would demonstrate a preference for features of the environment in which their ancestor evolved, such as relatively dense vegetation, within the outdoor range and that the behavioural time budget of hens will differ between distinct environments. Characteristics of the outdoor range in one free-range commercial egg farm were mapped and four distinct environments (‘locations’) were identified based on ground substrate and cover (Wattle Tree, Gum Tree, Bare Earth and Sapling). The number of hens accessing each location and behavioural time budget of these hens was recorded over a three-week period during the southern hemisphere summer (January-February). Hens showed a clear preference for the Wattle Tree and Gum Tree locations; however, a significant interaction between location and time of day suggested that the hens’ preference for different locations changed throughout the day. The most common behaviours displayed by hens were foraging, preening, locomotion, resting and vigilance, and most behaviours were influenced by the interaction between location and time of day. Overall, a wider variety of behaviours were performed in the highly preferred environments, but not all behaviours were performed equally within each environment throughout the day. Understanding what features hens prefer in the outdoor range and how this influences the performance of natural behaviours is important in promoting the welfare of hens in free-range production.

Keel-bone damage and foot injuries have a negative impact on welfare in laying hens. The extent of the problems in Danish commercial flocks of layers is unknown. Therefore, the aim of this study was to assess the current prevalence of keel-bone damage and foot injuries in Danish commercial flocks of laying hens and to investigate the effects of production system, housing system, hybrid and age. The occurrences of keel-bone damage, hyperkeratosis and missing toes were higher at 62 compared to 32 weeks of age, while the reverse was found for toe wounds, foot-pad lesions and bumble feet. There was no difference between barn and organic production systems in the risk of having keel-bone fractures and foot injuries, except that barn hens were more likely to have foot-pad lesions than organic hens (32 weeks: 16.1 vs 3.1%). Hens in multi-tiered systems were more likely to have keel-bone fractures compared to hens in single-tiered systems (62 weeks: 11.6 vs 4.9%). Of the four hybrids, Lohmann Brown Lite had a higher risk of keel-bone fractures, whereas bumble feet were found more frequently in Lohmann LSL Keel-bone damage and foot injuries are less common in Danish non-cage systems compared to most of the reporting presently available from other countries. We suggest transnational studies, aimed at identifying the causal factors of this discrepancy, to increase existing knowledge on how to reduce incidences of keel-bone damage and foot injuries.

Accelerometers are used to remotely monitor activity in various species in studies that quantify pain, document behavioural patterns, and measure individual activity differences. Studies validating accelerometers typically quantify various active states; however, targeting states specific to periods of inactivity, such as sitting, sleeping, and standing, has the potential to more accurately quantify inactive behaviours commonly associated with behavioural changes related to pain, sickness, or injury. Our objectives were two-fold: first, validate a commercially available accelerometer (Actical®) for quantifying inactivity in laying hens and, second, compare inactivity levels between hens with severely fractured keel bones and hens with minimal to no keel damage. Correlation between the inactivity level as measured by the accelerometer compared to live, focal observation of stationary, inactive behaviours was high; therefore, the Actical® accurately quantifies inactive states in laying hens. Following validation, the Actical® accelerometer was used to quantify inactivity level differences between hens with or without keel-bone damage. Severely fractured hens spent less time motionless, than hens with minimal to no keel damage. Further investigation into inactivity differences related to keel status before and after acquisition of keel fractures is warranted. Use of the accelerometer has the potential to improve animal welfare research by quantifying the effect of pain or sickness on activity level, mapping daily activity patterns, and measuring individual differences in general activity.

This study aimed to investigate the relationship between bone quality in terms of metabolism, homeostasis of elements, bone mineral density (BMD), and microstructure and keel-bone fractures in laying hens (Gallus gallus domesticus). One hundred and twenty 17 week old Lohmann White laying hens with normal keel bones were individually housed in furnished cages for 25 weeks. Birds were then euthanased and dissected to assess keel-bone status at 42 weeks. Serum and keel-bone samples from normal keel (NK) and fractured keel (FK) hens were collected to determine the previously mentioned bone quality parameters. The results showed FK hens to have higher levels of the components of osteocalcin, greater alkaline phosphatase activity in serum and keel bones, and greater tartrate-resistant acid phosphatase (TRAP) activity in keel bones, compared to NK hens. Additionally, FK hens also had higher concentrations of Li, B, K, Cu, As, Se, Sn, Hg, and Pb, but lower concentrations of Na, P, and Ca. Moreover, FK hens showed decreased bone microstructural parameters including bone volume/tissue volume, trabecular number, degree of anisotropy, connectivity density, and BMD, but increased trabecular separation. Meanwhile, no differences were detected in serum TRAP activity, trabecular thickness, bone surface, or bone surface/bone volume. Results showed laying hens with keel-bone fractures to have differences in bone metabolism, elements of home-ostasis, bone microstructure parameters, and BMD. These results suggest that keel-bone fractures may be associated with bone quality.

The poultry red mite (Dermanyssus gallinae) causes severe welfare concerns for laying hens arising from anaemia and disease transmission, and has been identified as an associated risk factor in cannibalistic feather pecking. Previous work suggests that essential oils may offer an alternative to synthetic acaricides to control D. gallinae. Such alternatives are needed due to the limitations of synthetic acaricides (eg availability, resistance, environmental concerns and product residues). The aim of the current study was to ensure that selected essential oils have no negative impact on either hen welfare or egg production. To achieve this aim, small groups of laying hens were confined in poultry huts for a period of eight weeks during which time the interior of the huts was sprayed at weekly intervals with one of four different treatments: i) Thyme essential oil at 5× the LC90 level (the concentration of oil previously found to kill 90% of D. gallinae under laboratory conditions) for D. gallinae in 500 ml of water, ii) Pennyroyal essential oil at 5× the LC90 level for D. gallinae in 500 ml of water, iii) Solvent-only (huts treated with 500 ml of water); and iv) Pseudo-spray where huts were not treated with any product, but subjected to sham-spraying. The results suggest that pennyroyal essential oil would not be suitable for further development as an acaricide for D. gallinae, since this treatment had to be terminated early in the study period as a result of concerns about the welfare of hens exposed to this oil. Conversely, there were few differences in feather condition, hen weight, feed intake, feeding efficiency, egg production or egg weight between thyme-treated huts and huts that were either pseudo-sprayed or sprayed with solvent-only (water). It is concluded that thyme essential oil is a promising candidate for further development as an acaricide for D. gallinae to help safeguard the welfare of laying hens in commercial poultry systems.