Developing a novel welfare assessment tool for loose-housed laying hens - the Aviary Transect method

Effects of Housing Systems on Production Performance, Egg Quality, Tonic Immobility and Feather Score in Laying Hens

BACKGROUND

This study was designed to investigate the effects of different housing systems on production performance, egg quality and welfare in laying hens.

METHODS

One hundred and twenty 42-week-old "Atak S" laying hens, purchased from a manufacturing company, were randomly assigned to 4 housing systems: conventional cages, furnished cages, deep-litter system and free-range. Each system housed 30 hens, which were kept in these systems for 6 weeks. Parameters regarding production performance, egg quality, plumage condition scores and tonic immobility were assessed at the end of the housing period.

RESULTS

Egg production and egg mass were lower in cage-free rearing systems than in caged systems. Mean egg weight in free-range hens, and albumen height and Haugh unit in deep-litter hens, were lower than in other housing systems. Eggshell weight in hens housed in furnished cages was greater than in free-range hens, while eggshell strength was better compared to that of hens in conventional cages. The housing system did not impact fearfulness; however, the deep-litter housing increased the sensitivity to touch or capture. Whole body and regional plumage condition scores of free-range hens elicited more favourable results than those kept in conventional cages. Because the plumage condition indicates welfare, the results proved the superiority of free-range over conventional rearing regarding welfare.

CONCLUSIONS

Concerning the parameters, such as egg production, animal welfare and fear level, overall data revealed the pros and cons of all housing systems investigated. We consider that this study's findings might contribute to the researchers and breeders seeking alternative housing for laying hens.

The potential of decision trees as a tool to simplify broiler chicken welfare assessments

To simplify fast-growth broiler welfare assessments and use them as a benchmarking tool, decision trees were used to identify iceberg indicators discriminating flocks passing/failing welfare assessments as with the complete AWIN protocol. A dataset was constructed with data from 57 flocks and 3 previous projects. A final flock assessment score, previously not included in the dataset, was calculated and used as the benchmarking assessment classifier (pass/fail). A decision tree to classify flocks was built using the Chi-square Automatic Interaction Detection (CHAID) criterion. Cost-complexity pruning, and tenfold cross-validation were used. The final decision tree included cumulative mortality (%), immobile, lame birds (%), and birds with back wounds (%). Values were (mean ± se) 2.77 ± 0.14%, 0.16 ± 0.02%, 0.25 ± 0.02%, and 0.003 ± 0.001% for flocks passing the assessment; and 4.39 ± 0.49%, 0.24 ± 0.05%, 0.49 ± 0.09%, and 0.015 ± 0.006% for flocks failing. Cumulative mortality had the highest relative importance. The validated model correctly predicted 80.70% of benchmarking assessment outcomes. Model specificity was 0.8696; sensitivity was 0.5455. Decision trees can be useful to simplify welfare assessments. Model improvements will be possible as more information becomes available, and predictions are based on more samples.

Effect of light sources with and without UVA on selected behavior and health indicators in commercial broiler breeder flocks

As new light sources are being developed for poultry houses, systematic investigations on how these influence behavior and health in commercial broiler breeders are needed. Therefore, the aim of this study was to investigate the effects of 2 light sources (Evolys with UVA (LED) and Biolux 965 (CFL)) on the behavior and health of 2 broiler breeder hybrids during the production period. Eight commercial breeder flocks (Ross 308 n = 4, Hubbard JA757 n = 4) with Evolys (Ross n = 2, Hubbard n = 2) or Biolux (Ross n = 2, Hubbard n = 2) were visited at 25 and 50 wk of age to record behavior and health. Behaviors included resting, locomotion, exploration, comfort, feather pecking, aggression, and mating, while health was recorded by a transect walk, scoring the number of birds observed with: feather loss (FL) on head, back/wings, breast, and tail, wounds on head, back/wings, and tail, dirty plumage, lameness, sickness, and dead birds. The most common behaviors were resting, locomotion, comfort, and exploration, and these were influenced by a 3-way interaction between light source, hybrid, and age. Light source did not affect behavior in Hubbard birds at any age. In contrast, Ross birds housed in Evolys rested less at 50 wk compared to Biolux (P = 0.04) and showed more locomotion at 25 wk in Biolux compared to Evolys (P < 0.0001). Ross birds at 25 wk explored more in Biolux compared to Evolys (P = 0.0007). More comfort behavior was performed in Evolys in 25-wk-old Ross (P = 0.002), but not at 50 wk. These inconsistencies might be due to low sample size, which is a limitation in the study. The most common health indicators were FL on back/wings (mean 3.9%), wounds on back/wings (mean 0.22%), and FL head (mean 0.18%), with no effect of light source, hybrid, or age on FL back/wings, breast, or tail, but with increased FL on the head with increased age (P = 0.0008). In conclusion, the behavior of Ross birds seemed to be affected by light source, while the Hubbard birds were not. Light source had minor effects on the selected health indicators in the 2 hybrids.

Development and evaluation of an animal health and welfare monitoring system for veterinary supervision of pullet farms

Regular welfare monitoring throughout rearing of pullets may help to identify problems early and take counteractions timely, which helps in guaranteeing good welfare. The aims of our observational study were (i) to establish and test a welfare monitoring system that can be used during (short) routine veterinary and technical staff visits for pullet flocks, (ii) to use the monitoring system to investigate variability between flocks and (iii) to analyse factors that potentially affect pullets' body weight, uniformity in body weight and mortality. The developed monitoring system tries to minimise the time required while not losing important information. Age-specific recording sheets comprise animal-based indicators of welfare and relevant environmental factors (housing, management, care) to allow for identifying causes of problems and targeted action. Finally, the system was implemented in a cross-sectional study and data collected in 100 flocks (67 organic, 33 conventional) on 28 rearing farms in Austria. Linear mixed models were used to identify factors influencing body weight, uniformity and mortality, both including all flocks (A) and only organic flocks (O) and a linear regression model with all flocks to investigate associations within animal-based indicators. High variability was found between flocks in animal-based indicators. Body weight was higher when the pre-rearing period was shorter (p ≤ 0.001, A&O), with higher intensities of light (p = 0.012, O), with only one compared to more stockpersons (p ≤ 0.007, A&O), with a higher number of flock visits per day (p ≤ 0.018, A&O), and a lower avoidance distance (p = 0.034, A). Body weight uniformity increased, with age and decreased with the duration of the light period (p = 0.046, A), and, amongst others, was higher on organic farms (farming type; p = 0.041). The latter may reflect a more uniform level of welfare due to a lower stocking density and lowered effects of social competition. Within organic flocks mortality was lower if pullets had access to a covered veranda (p = 0.025) resulting in an overall lower stocking density inside the barn, while in the model including all farms mortality was higher in cases where a disease had been diagnosed. We conclude that our monitoring system can easily be implemented in regular veterinary and technical staff visits, but could also be used by the farmers'. Several easy-to-record animal-based indicators of animal welfare could be analysed more frequently to increase early detection of problems. Implementation of such a routine-based monitoring system with easy-to-assess animal-based parameters and input measures can contribute to better animal health and welfare in pullets.

The Aviary Transect - A practical welfare assessment tool to improve the management of cage-free laying hens

The Aviary Transect (AT) is a method for assessing welfare in cage-free laying hen flocks, and comprises standardized walks along each aisle screening the flock for selected welfare indicators: feather loss (FL) on head, back, breast, and tail, wounds on head, back, tail, and feet, dirty plumage, enlarged crop, sickness, and birds found dead. The method is quick (20 min for a flock of 7,500 hens), has good interobserver agreement and shows positive correlations with individual bird sampling methods. However, it is less clear whether AT can be used to detect differences in flock health and welfare related to housing and management. The aim of this study was to evaluate how AT findings varied in relation to 23 selected housing, management, environmental, and production factors. The study was conducted on 33 commercial nonbeak-trimmed, white-feathered layer flocks of similar age (70-76 wk) kept in multitiered aviaries in Norway. The most prevalent findings across flocks were feather loss on the back (mean 0.97% of flock) and breast (0.94%) followed by feather loss on the head (0.45%) and tail (0.36%) with differences in feather pecking damage according to the hybrid used (P < 0.05). Better litter quality was associated with a lower prevalence of feather loss on the head and breast (P < 0.05), and addition of fresh litter during the production cycle resulted in fewer birds with feather loss on the head (P < 0.05) and tail (P < 0.001). Lower dust levels were linked to a lower prevalence of feather loss on the head, back, and breast (P < 0.05), and when access to the floor area underneath the aviary was provided at an earlier stage of production, fewer birds had wounds (P < 0.001), but more birds were observed with an enlarged crop (P < 0.05) and found dead (P < 0.05). In conclusion, findings from AT showed that results of the assessment varied according to housing conditions. These results support the validity of AT as a relevant welfare assessment tool for evaluating cage-free management practices.

EFSA AHAW Panel (EFSA Panel on Animal Health and Welfare), Nielsen SS, Alvarez J, Bicout DJ, Calistri P, Canali E, Drewe JA, Garin‐Bastuji B, Gonzales Rojas JL, Schmidt CG, Herskin MS, Miranda Chueca MÁ, Padalino B, Pasquali P, Roberts HC, Spoolder H, Stahl K, Velarde A, Viltrop A, Winckler C, Tiemann I, de Jong I, Gebhardt‐Henrich SG, Keeling L, Riber AB, Ashe S, Candiani D, García Matas R, Hempen M, Mosbach‐Schulz O, Rojo Gimeno C, Van der Stede Y, Vitali M, Bailly‐Caumette E, Michel V. Welfare of broilers on farm

This Scientific Opinion considers the welfare of domestic fowl (Gallus gallus) related to the production of meat (broilers) and includes the keeping of day-old chicks, broiler breeders, and broiler chickens. Currently used husbandry systems in the EU are described. Overall, 19 highly relevant welfare consequences (WCs) were identified based on severity, duration and frequency of occurrence: 'bone lesions', 'cold stress', 'gastro-enteric disorders', 'group stress', 'handling stress', 'heat stress', 'isolation stress', 'inability to perform comfort behaviour', 'inability to perform exploratory or foraging behaviour', 'inability to avoid unwanted sexual behaviour', 'locomotory disorders', 'prolonged hunger', 'prolonged thirst', 'predation stress', 'restriction of movement', 'resting problems', 'sensory under- and overstimulation', 'soft tissue and integument damage' and 'umbilical disorders'. These WCs and their animal-based measures (ABMs) that can identify them are described in detail. A variety of hazards related to the different husbandry systems were identified as well as ABMs for assessing the different WCs. Measures to prevent or correct the hazards and/or mitigate each of the WCs are listed. Recommendations are provided on quantitative or qualitative criteria to answer specific questions on the welfare of broilers and related to genetic selection, temperature, feed and water restriction, use of cages, light, air quality and mutilations in breeders such as beak trimming, de-toeing and comb dubbing. In addition, minimal requirements (e.g. stocking density, group size, nests, provision of litter, perches and platforms, drinkers and feeders, of covered veranda and outdoor range) for an enclosure for keeping broiler chickens (fast-growing, slower-growing and broiler breeders) are recommended. Finally, 'total mortality', 'wounds', 'carcass condemnation' and 'footpad dermatitis' are proposed as indicators for monitoring at slaughter the welfare of broilers on-farm.

Flock Factors Correlated with Elevated Mortality in Non-Beak Trimmed Aviary-Housed Layers

The use of non-cage housing systems for layers is increasing in Europe and elsewhere. Knowledge of factors that may affect mortality in these systems is important to be able to improve animal welfare, reduce mortality and enhance sustainability. The aim of this study was to investigate factors that may contribute to increased mortality in non-beak trimmed aviary-housed laying hens in Norway. A total of 39 non-beak trimmed commercial flocks (Lohmann LSL (n = 25) and Dekalb White (n = 14)) were visited between week 70 to 76 of life, and factors related to health, behaviour and management were recorded. Mean mortality in the flocks was 3% (range: 0.5−9%) and increased flock mortality was correlated with total feather loss (p < 0.05); feather loss on the breast (p < 0.02) and feather loss on the head (p < 0.003). There was an association between layer hybrid line and mortality (p = 0.055). Furthermore, a low positive correlation between mortality and dust level inside the barn was found (p < 0.04), showing that mortality was higher when dust level was also high. No correlation between mortality and the provision of environmental enrichment was found. In conclusion, this study found an association between flocks with elevated mortality (>3.0%) and increased feather loss which may indicate feather pecking. The results underline the importance of regularly assessment of plumage condition in commercial layer farms, as a tool to detect early signs of feather pecking in commercial aviary-housed layer flocks. This may help to target feather pecking before cannibalism breaks out.

The Relationships between Damaging Behaviours and Health in Laying Hens

Since the ban in January 2012 of conventional cages for egg production in the European Union (Council Directive 1999/74/EC), alternative systems such as floor, aviary, free-range, and organic systems have become increasingly common, reaching 50% of housing for hens in 2019. Despite the many advantages associated with non-cage systems, the shift to a housing system where laying hens are kept in larger groups and more complex environments has given rise to new challenges related to management, health, and welfare. This review examines the close relationships between damaging behaviours and health in modern husbandry systems for laying hens. These new housing conditions increase social interactions between animals. In cases of suboptimal rearing and/or housing and management conditions, damaging behaviour or infectious diseases are likely to spread to the whole flock. Additionally, health issues, and therefore stimulation of the immune system, may lead to the development of damaging behaviours, which in turn may result in impaired body conditions, leading to health and welfare issues. This raises the need to monitor both behaviour and health of laying hens in order to intervene as quickly as possible to preserve both the welfare and health of the animals.

Environmental enrichment in commercial flocks of aviary housed laying hens: relationship with plumage condition and fearfulness

Management strategies can have positive effects on laying hen welfare, including prevention of damaging behavior, aggression, and fear, particularly by using environmental enrichment (EE). However, few studies have investigated the effects of the provision of EE in commercial aviary flocks. This knowledge gap is particularly significant considering the increasing numbers of non-beak trimmed hens worldwide kept in aviaries. The aim of this study was to survey and investigate the relationship between commercially applied EE and plumage condition and fearfulness in Norwegian flocks of loose-housed laying hens. Forty-five indoor multi-tiered aviary-system flocks of laying hens from across Norway were visited at the end of lay (range: 70–76 wk of age). The flocks consisted of either Lohmann LSL (n = 30) or Dekalb White (n = 15) non–beak-trimmed hens. During the visit, the researchers collected data on the farmers’ use of the following five types of enrichment: pecking stones, gravel, oyster shells, grains scattered in the litter, and “toys”. Feather loss was assessed individually in approximately 50 hens per flock and scores were awarded using a 3-point scale (0–2) for each of the following body parts: head, back/wings, breast, and tail. Finally, a novel object test was performed in 4 different locations in each house. The results showed that damage to the tail feathers was correlated positively to the first age of provision of toys (Pearson correlation coefficient = 0.41; P = 0.051) and negatively to the amounts of gravel stones provided (Pearson correlation coefficient = −0.43, P = 0.02). No other associations between the welfare indicators and the provision of EE objects were found, likely because of the low variation of enrichment provision. The present study showed that the provision of EE objects such as toys and gravel stones can have significant benefits to the condition of laying hen plumage. This study also adds to the body of literature supporting the importance of early life experiences on the behavioral development of laying hens and on their welfare at older ages.