Lauren E. Edwards

For modern layers to achieve optimum production performance and welfare state, the entire production process needs to be managed to achieve target bodyweight, body composition and flock uniformity. In addition to genetic improvements, flock health, environment, nutrition and on-farm husbandry practices, incubation and hatchery practices have become a focal point for producing optimum chick quality. Chick quality is a collective term involving chick size and anatomical features, physiology, robustness and liveability over the first week after placement. Chick quality is a key focus for hatcheries as this has been positively correlated with overall flock performance, especially egg production, shell quality, liveability and animal welfare. Recent advances in incubation have focussed on the benefits of all-in–all-out (single-stage) machines. Innovation in incubation systems is completely conducted today by international manufacturers, and is largely driven by the meat chicken industry. Disposal of male layer chicks has increased as a consumer welfare concern, and while investment in research and legislation changes are focussed towards providing or driving new solutions, there are currently no commercial options for industry to deal with this problem before incubation or hatch. Chick transport systems and equipment have also significantly improved in recent years, providing optimum conditions to ensure temperature uniformity and minimal moisture loss during transit before placement, thus optimising chick quality. Together, recent improvements in incubation equipment and hatchery practice can produce commercial layer chicks that are healthy, of high quality, and are then in an optimal physiological state and condition to achieve their genetic potential.

The present review examines the impact of management and husbandry decisions on the welfare of laying hens in Australia. The literature on many of these aspects is lacking for the Australian egg industry, and, indeed, for the egg industry in general. Management decisions that can affect hen welfare relate to the initial farm design, husbandry routines, and staff selection and training. As modern laying houses represent a considerable financial investment, the decisions made during the design phase are likely to affect both the hens and stockpeople for substantial periods. Hens in cage systems may benefit from fewer tiers and greater space allowances. In non-cage systems, the brown genotypes used in the Australian egg industry may benefit from lower structures that accommodate their heavier and less agile bodies. Keel fractures can be reduced by improving the skeletal health and spatial cognition of laying hens during the rearing period, in addition to minimising the distances they need to jump when navigating aviary structures. The addition of a wintergarden to fixed free-range systems appears to be beneficial. Housing hens in mobile units on free-range farms may challenge their welfare, particularly in relation to heat stress. There is also room for improvement in biosecurity practices and health monitoring of hens, as these appear to be lacking at some farms. The current strains of hen used in free-range systems may not be best suited to these conditions, on the basis of their body condition and flock uniformity. Feed quality may also need to be monitored for quality assurance and optimal hen nutrition. Hen welfare during depopulation can be improved through staff training and by reducing staff fatigue. Euthanising spent hens on farm offers welfare benefits over transporting spent hens to an abattoir. Both hen welfare and working conditions for stock people should be considered when designing laying houses to provide suitable conditions for both hens and stockpeople. This will help improve the job satisfaction of stockpeople, which may translate into better care for the hens and may aid in retaining quality staff. Stockpeople must be recognised as vital contributors to hen welfare in the egg industry, and it is important for the egg industry to continue to attract, train and retain skilled stockpeople to ensure that they enjoy their job and are motivated to apply best-practice care for their flocks. Promoting the animal-care aspect of stockmanship in combination with a supportive managerial environment with optimal working conditions may increase the attractiveness of the egg industry as a place to work.

Some believe that farm animals need to be kept in conditions that provide ‘natural’ aspects in the animal’s environment and, thus, provide the opportunity for the animals to perform their full ‘behavioural repertoire’. Captivity may restrict either behaviours that animals have instinctive, intrinsic propensities to perform whatever the environment or behaviours that are elicited by deficits in the animals’ environment. Behavioural restriction may also thwart general motivation to seek variety and/or avoid monotonous conditions. Appreciating whether an animal suffers if deprived of the opportunity to perform natural behaviour requires, first, an understanding of how the behaviour in question is elicited and controlled, the effects of early experience and genetics on the behaviour and the behaviour of the species in the wild, and, second, the behavioural, physiological and fitness effects of deprivation of the behaviour. Housing laying hens in conventional cages compromises their behavioural repertoire, such as nesting in a nest box, dust bathing, perching and foraging, and the present review focuses on the welfare implications if these natural behaviours are thwarted in modern poultry production. A floor space of <561 cm2/hen increases physiological stress, reduces egg production and increases mortality in laying hens. There is also evidence of behavioural restriction in terms of reduced wing stretching, leg stretching, tail wagging, locomotion, floor and object pecking and preening with floor space in the range of 542–750 cm2/hen. Preference and motivation research has indicated that laying hens value resources such as nest boxes for oviposition, substrates for foraging and dust bathing, and perches for roosting. However, there is no convincing evidence that deprivation of these resources results in physiological stress. Furthermore, apart from adverse effects of the absence of perches on bone strength, there is no evidence that deprivation of nest boxes, perches, and foraging and dust-bathing substrates results in reduction in fitness such as reduced egg production or health. Nevertheless, preference research has indicated that the opportunity to utilise these resources, particularly nest boxes, may elicit positive emotional states in laying hens. Therefore, it is important to understand both how motivated the animal is to choose an option or perform a behaviour as well as the consequences of depriving the animal of this opportunity.

Studies on farm animals have shown relationships between stockperson attitudes and behaviour and farm animal fear, stress and productivity. This study investigated how the avoidance behaviour of Australian commercial caged laying hens may be related to stockperson behaviour, albumen corticosterone, and the number of weeks producing within 5% of peak egg production. Nineteen laying houses were assessed over 3 days. Fear of humans in hens, based on their avoidance response to an unfamiliar human, was assessed using two behavioural tests. Albumen corticosterone concentrations were measured from egg samples collected immediately prior to behavioural testing. Stockperson attitudes were assessed using a questionnaire and stockperson behaviour was observed over 2 days. Productivity records for each laying house were also obtained. The duration of peak production was negatively related to both noise made by the stockperson and hen avoidance. No relationship between stockperson behaviour or attitudes and hen avoidance was found, but stockpeople with negative attitudes made more noise. In conclusion, this study could not confirm a relationship between stockperson behaviour and hen avoidance behaviour for Australian caged laying hens. However, this study did confirm a relationship between hen avoidance behaviour, albumen corticosterone concentration, and the duration of peak egg production.

Human interactions, particularly negative ones, affect the behaviour and physiology of laying hens, with possible implications for bird productivity and welfare. The present experiment investigated the effects of handling on the behaviour and plasma corticosterone concentrations of laying hens. A 2 × 2 × 3 factorial design was used to study the following three main effects: human contact during rearing [an additional 12 min of human contact per day (AC) or no additional contact (MC) during rearing]; handling quality in adulthood [brief daily exposure to positive (+ve) or negative (–ve) visual contact with a human]; and handling proximity in adulthood [handling-quality treatment (+ve or –ve) imposed at the following three distances from the birds: Near, 0–45 cm; Middle, 45–75 cm, or Far, 75–105 cm]. AC during rearing resulted in reduced avoidance behaviour of humans during adulthood, whereas handling imposed at the Far level resulted in greater avoidance behaviour than did handling at the Near or Middle level. The quality of the handling (+ve or –ve) had little effect on avoidance behaviour; however, there was a trend (P = 0.07) for hens receiving +ve handling to have a lower corticosterone response to human contact than those receiving –ve handling. These results demonstrate that visual human contact can influence the avoidance behaviour of laying hens.