Broiler chickens dead on arrival: associated risk factors and welfare indicators

Upright versus inverted catching and crating end-of-lay hens: a trade-off between animal welfare, ergonomic and financial concerns

This study explores upright versus inverted catching and crating of spent laying hens. Both catching methods were compared using a cost-benefit analysis that focused on animal welfare, ergonomic, and financial considerations. Data were collected on seven commercial farms (one floor system and six aviary systems) during depopulation of approximately 3,000 hens per method per flock. Parameters such as wing flapping frequency, catcher bird interaction, incidence of catching damage and hens dead on arrival (DOA) were measured and compared between catching methods. Ergonomic evaluations were performed via catcher surveys and expert assessment of video recordings. The wing flapping frequency was lower (3.1 ± 0.6 vs. 4.0 ± 0.5, P < 0.001) and handling was gentler (1.9 ± 0.5 vs. 4.4 ± 0.5, P < 0.001), both on a 7-point Likert scale, for upright versus inverted catching. However, more person-hours per 1000 hens were required for upright than inverted catching (8.2 ± 3.2 h vs. 4.8 ± 2.0 h, P = 0.011), with only wing bruises being significantly less common for upright than inverted catching (1.1 ± 0.6 % vs. 1.7 ± 0.7%, P = 0.04). Upright catching was 1.8 times more expensive than inverted catching; compensation for this cost would require a premium price of approximately €0.0005 extra per egg. Ergonomically, both catching methods were considered demanding, although catchers (n = 29) preferred inverted catching. In conclusion, this study showed animal welfare benefits of upright vs. inverted catching. Industry adoption of upright catching will depend on compensation of the additional labor costs, adjustments to labor conditions and shorter loading times.

Machine learning predictive modeling for condemnation risk assessment in antibiotic-free raised broilers

The condemnation of broiler carcasses in the poultry industry is a major challenge and leads to significant financial losses and food waste. This study addresses the critical issue of condemnation risk assessment in the discarding of antibiotic-free raised broilers using machine learning (ML) predictive modeling. In this study, ML approaches, specifically least absolute shrinkage and selection operator (LASSO), classification tree (CT), and random forests (RF), were used to evaluate and compare their effectiveness in predicting high condemnation rates. The dataset of 23,959 truckloads from 2021 to 2022 contained 14 independent variables covering the rearing, catching, transportation, and slaughtering phases. Condemnation rates between 0.26% and 25.99% were used as the dependent variable for the analysis, with the threshold for a high conviction rate set at 3.0%. As high condemnation rates were in the minority (8.05%), sampling methods such as random over sampling (ROS), random under sampling (RUS), both sampling (BOTH), and random over sampling example (ROSE) were used to account for imbalanced datasets. The results showed that RF with RUS performed better than the other models for balanced datasets. In this study, mean body weight, weight per crate, mortality and culling rates, and lairage time were identified as the 4 most important variables for predicting high condemnation rates. This study provides valuable insights into ML applications for predicting condemnation rates in antibiotic-free raised broilers and provides a framework to improve decision-making processes in establishing farm management practices to minimize economic losses in the poultry industry. The proposed methods are adaptable for different broiler producers, which increases their applicability in the industry.

Analysis of the Broiler Chicken Dead-on-Arrival (DOA) Rate in Relation to Normal Transport Conditions in Practice in Germany

In total, around 631 million broilers were slaughtered in Germany in 2022. This evaluation included data of approx. 198 million broilers of different ages and breeds that were transported in Germany in 2022 (31% of all cases of broiler chicken transport in 2022). The aim of this study was to analyze German broiler chicken transport (n = 14,054) to the slaughterhouse between January 2022 and May 2023 with regard to the dead-on-arrival (DOA) rate and the possible influencing factors. Therefore, the relation between the total amount of animals per transport, the duration and distance of the transport, the planned stocking density in the transport cages, the average daily temperature and time of day and season of the transport as well as the DOA rate were statistically evaluated. The results showed a mean DOA rate of 0.09% (SD 0.09). Transport conducted at midday (11:00 to 17:00) showed higher DOA rates (p < 0.05) than transport at other times (day split into 6 h intervals). The highest mean DOA rate (0.10%) was found in the fall, followed by the winter, while transport in the spring and summer resulted in the lowest DOA rate (p < 0.05). All in all, the relatively low DOA rate (%) in Germany indicates the good standard of their broiler transport compared to available data from research in other European countries.

Water deprivation in poultry in connection with transport to slaughter-a review

Poultry are deprived of water when transported to slaughter, beginning shortly prior to catching of the first bird and lasting through catching and loading, the journey on the vehicle, time spent in lairage, and up until time of death. Our aim was to review existing knowledge on variables which may be useful in determining the length of time that poultry may go without water in connection with transport before their welfare begins to deteriorate. During transport, it is likely that birds experience a motivation to drink, which may transition into the negative emotional state of thirst if water is unavailable. Determining when drinking motivation reaches a threshold where welfare is negatively impacted is challenging. In the absence of water, birds may over time experience dehydration which may be detected through physiological indicators as their body attempts to maintain homeostasis. In poultry, plasma osmolality, arginine vasotocin, and chloride have been suggested as being most suitable for assessing dehydration resulting from periods of water deprivation that correspond with typical transport durations, due to their particular sensitivity during this period. While initial dehydration may not be associated with negative emotional states, it is likely that it eventually leads to discomfort, but additional behavioral and motivational studies are necessary to infer when this begins. Impacts of thermal conditions, genetics, and the condition of the individual bird on the development of a dehydrated state were also assessed, though more information is needed to fully understand these interactions. With the available literature, this review concludes that total transport (i.e., from the initial deprivation from water until time of slaughter) durations of longer than 6 h are likely associated with measurable physiological indicators of dehydration and may potentially be associated with negative emotional states, although more research is needed to clarify this. Current available knowledge and assessment tools are not sufficient to detect the degradation of welfare derived from thirst itself, which should be further examined to protect poultry welfare during transport.

Application of machine learning algorithms to predict dead on arrival of broiler chickens raised without antibiotic program

Understanding the factors of dead-on-arrival (DOA) incidents during pre-slaughter handling is crucial for informed decision-making, improving broiler welfare, and optimizing farm profitability. In this study, 3 different machine learning (ML) algorithms - least absolute shrinkage and selection operator (LASSO), classification tree (CT), and random forest (RF) - were used together with 4 sampling techniques to optimize imbalanced data. The dataset comes from 22,115 broiler truckloads from a large producer in Thailand (2021-2022) and includes 14 independent variables covering the rearing, catching, and transportation stages. The study focuses on DOA% in the range of 0.10 to 1.20%, with a threshold for high DOA% above 0.3%, and records DOA% per truckload during pre-slaughter ante-mortem inspection. With a high DOA rate of 25.2%, the imbalanced dataset prompts the implementation of 4 methods to tune the imbalance parameters: random over sampling (ROS), random under sampling (RUS), both sampling (BOTH), and synthetic sampling or random over sampling example (ROSE). The aim is to improve the performance of the prediction model in classifying and predicting high DOA%. The comparative analysis of the different error metrics shows that RF outperforms the other models in a balanced dataset. In particular, RUS shows a significant improvement in prediction performance across all models compared to the original unbalanced dataset. The identification of the 4 most important variables for predicting high DOA percentages - mortality and culling rate, rearing stocking density, season, and mean body weight - emphasizes their importance for broiler production. This study provides valuable insights into the prediction of DOA status using an ML approach and contributes to the development of more effective strategies to mitigate high DOA percentages in commercial broiler production.

Preslaughter handling factors affecting dead on arrival, condemnations, and bruising in broiler chickens raised without an antibiotic program

In Thailand, knowledge about the factors affecting broiler losses during the preslaughter process is very limited, especially for broilers raised without an antibiotic program. The objective of this study was to determine the preslaughter factors that influence the incidence of dead on arrival (DOA), condemnations, and bruising in broilers raised without antibiotics. Data from 13,581 truckloads of broilers raised without an antibiotic program in 95 contract farms of one of Thailand's largest broiler producers in 2021 were analyzed using a generalized linear mixed model that accounted for farm as a random effect. Results showed that the following risk factors were associated with the occurrence of DOA, condemnations, and bruising: season, time of transport, sex, age at slaughter, mortality and culling rate, and weight per crate. While mean body weight affected the incidence of condemnations and bruising, transport time and lairage time affected DOA and bruising. Feed withdrawal time affected DOA and condemnations. Rearing stocking density only affected condemnation rate. Reducing or eliminating the effects of these risk factors could reduce production losses due to DOA, condemnations, and bruising, thereby improving animal welfare and producer profitability. Reducing weight per crate could reduce DOA, condemnations, and bruising. Reducing lairage time could reduce DOA and bruising, while reducing feed withdrawal time could reduce DOA and condemnations. Raising broilers at a younger age with a lower slaughter weight could prevent the occurrence of DOA, condemnations, and bruising.

Effects of external ambient temperature at loading, journey duration and flock characteristics on the dead-on-arrival rate in broiler chickens transported to slaughter in Great Britain

Broiler mortality during transport and lairage, prior to slaughter, has negative welfare and economic implications. Knowledge of the factors affecting the dead-on-arrival (DOA) rate can help identify risk-mitigating strategies. The objectives of this study were to determine the DOA rate in broiler chickens transported to slaughter in Great Britain and associated risk factors. Requested data for all loads of broilers transported to slaughter by 5 large British commercial companies on 57 randomly-selected dates in 2019 were obtained and combined with weather data extracted from the Met Office MIDAS Open database. The DOA rate was described overall and per load using summary descriptive statistics. Mixed-effects Poisson regression was used to evaluate considered flock-, journey- and weather-related risk factors. Results were reported as incidence rate ratios (IRR) and 95% confidence intervals (CI). On the selected dates, 25,476 loads transported 146,219,189 broilers to slaughter. The overall mean DOA rate was 0.08%. The median DOA rate per load was 0.06% (interquartile range 0.03-0.09%; range 0.00-17.39%). Multiple risk factors were identified including loading temperature and catch method. At relative humidity ≤80%, the DOA rate was 16.89 (95% CI 15.25-18.70, P < 0.001) times higher for loads loaded in external ambient temperatures >30.0°C compared to those loaded in temperatures between 10.1°C and 15.0°C. When relative humidity was >80%, there was a 43% increase in DOA rate for loads loaded in temperatures below freezing compared to those loaded in temperatures between 10.1°C and 15.0°C (IRR 1.43, 95% CI 1.35-1.52, P < 0.001). The DOA rate was 32% higher for loads caught mechanically compared to those caught manually (IRR 1.32, 95% CI 1.23-1.42, P < 0.001). The overall DOA rate was lower than that previously reported in Great Britain and for other European countries. Most identified risk factors had a marginal effect, however, loading temperatures >30°C substantially increased DOA rate. Internal thermal environmental conditions were not evaluated. Avoidance of loading during periods of hot weather would improve the welfare of, and reduce economic losses in, broiler chickens.

The effect of water shower spray on stress physiology and mortality in broiler chickens subjected to road transportation under the hot and humid tropical condition

This study was performed to investigate the effect of water shower spray on rectal temperature (RT), serum levels of corticosterone (CORT), heat shock protein (HSP) 70 and creatine kinase (CK) in broiler chickens road transported at different times of the day. A total of 320 male broiler chickens (35 days of age) were crated and subjected to either water shower spray (WS) for 10 min or no water shower (control). The WS and control broilers were then loaded into an open truck and transported either from 0900 to 1100 h (29.0 °C and 89.0% RH) (AM) or 1900 h to 2100 h (26.0 °C and 94.0% RH) (PM) with an average speed of 80 km/h. The CORT of AM birds were significantly reduced by WS, but the treatment had negligible influence on the PM group. Transportation during AM significantly elevated RT, CORT and HSP70 compared to the PM group. Water shower spraying of birds before transit significantly reduced RT and HSP70 compared to controls. Neither water shower treatment nor transportation time had a significant on CK and mortality rate of broilers. In conclusion, water shower spray is beneficial to alleviate the physiological stress response in road-transported broilers under the hot and humid tropical environment.

Data evaluation of broiler chicken rearing and slaughter-An exploratory study

To process and evaluate the data from broiler fattening and slaughtering, we investigated the production data of 107 straight run flocks of the commercial meat-type breed Ross 308 (Aviagen, EU). All flocks were raised and slaughtered in Germany and the average slaughter age was 37 days. The health outcomes of interest were mortality, average weight, and the slaughter results. First-week mortality, cumulative mortality, stocking density, flock size, season, production week of the parental flock, farm, antibiotic treatment, and the interaction between antibiotic treatment and season were considered as possible influencing factors. The average first-week mortality (FWM) and cumulative mortality percentages were 0.66 and 2.74%, respectively. First-week mortality was influenced by flock size, production week of the parental flock, and the interaction between antibiotic treatment and season, whereas cumulative mortality was influenced by antibiotic treatment, farm, and first-week mortality. The average weight (mean 2.30 kg) was influenced by season, stocking density, flock size, farm, and the interaction between antibiotic treatment and season. The condemnation rate was on average 1.48%, with the most common causes being deep dermatitis (mean 0.63%), ascites (mean 0.53%), and not suitable for production/general disease (mean 0.25%). Several factors influenced the causes of condemnation, with season being the most predominant one, followed by the interaction between antibiotic treatment and season, the antibiotic treatment alone, and stocking density.

Welfare of domestic birds and rabbits transported in containers

This opinion, produced upon a request from the European Commission, focuses on transport of domestic birds and rabbits in containers (e.g. any crate, box, receptacle or other rigid structure used for the transport of animals, but not the means of transport itself). It describes and assesses current transport practices in the EU, based on data from literature, Member States and expert opinion. The species and categories of domestic birds assessed were mainly chickens for meat (broilers), end-of-lay hens and day-old chicks. They included to a lesser extent pullets, turkeys, ducks, geese, quails and game birds, due to limited scientific evidence. The opinion focuses on road transport to slaughterhouses or to production sites. For day-old chicks, air transport is also addressed. The relevant stages of transport considered are preparation, loading, journey, arrival and uncrating. Welfare consequences associated with current transport practices were identified for each stage. For loading and uncrating, the highly relevant welfare consequences identified are handling stress, injuries, restriction of movement and sensory overstimulation. For the journey and arrival, injuries, restriction of movement, sensory overstimulation, motion stress, heat stress, cold stress, prolonged hunger and prolonged thirst are identified as highly relevant. For each welfare consequence, animal-based measures (ABMs) and hazards were identified and assessed, and both preventive and corrective or mitigative measures proposed. Recommendations on quantitative criteria to prevent or mitigate welfare consequences are provided for microclimatic conditions, space allowances and journey times for all categories of animals, where scientific evidence and expert opinion support such outcomes.

The welfare impacts of mechanical and manual broiler catching and of circumstances at loading under field conditions

Loading of broilers for transport to the processing plant poses a notable injury risk for broilers. Therefore, the poultry industry has developed mechanical methods as alternatives to manual loading methods. Our objective in the present study was to compare manual loading (MAN) of broilers with the mechanical loading (MECH). We assessed the injuries of broilers of 12 MAN and 12 MECH flocks on-farm before and immediately after loading, documented the numbers of broilers dead on arrival reported by the processing plant, and assessed the circumstances at loading. A smaller number of broilers with a hematoma (≥0.5 cm in diameter) on the wing were observed after MAN compared with MECH using the examined harvester (MAN vs. MECH odds ratio: 0.16; 95% confidence interval: 0.10, 0.28). The number of broilers with severe wing injuries did not differ between the loading methods. The number of broilers dead on arrival was greater in mechanically loaded flocks (MAN vs. MECH odds ratio: 0.26; 95% confidence interval: 0.10, 0.68), but lower than in comparable studies. We observed a lower average stocking rate than targeted in the drawers of MECH containers, most likely because the used harvester can adapt to short-term changes in weight and adjust the stocking rate during the loading process. A longer total loading duration in MAN was associated with an increase of wing hematomas, and the involvement of more working people per 10,000 broilers during MAN was associated with a lower occurrence of hematomas. The total loading duration in MECH had no notable influence on the occurrence of injuries. Physical conditions of the involved personnel might play a larger role in MAN than in MECH. The harvester that was examined should be further developed to reduce the occurrence of hematomas. Our results indicate that the choice of loading method alone does not determine the injury risk, and multiple factors are associated with broiler welfare during loading. It is important that the chosen method is performed under the most adequate conditions.

Associations between welfare and ranging profile in free-range commercial and heritage meat-purpose chickens (Gallus gallus domesticus)

Despite consumers' belief that access to an outdoor range improves chicken welfare, still little is known about whether this is true and whether individual ranging profiles relate to the birds' welfare. The aim of the present study was to identify and compare welfare issues of the traditional broiler hybrid Sasso and the Polish heritage chicken Green-legged Partridge, having outdoor access, and examine if the birds' welfare status was associated with the ranging profile: outdoor-preferring, moderate-outdoor, and indoor-preferring. In August 2018, 60 non-beak trimmed birds per genetic strain were housed in groups of 10 from weeks 5 to 10, under conditions exceeding EU requirements of organic meat chicken production. Each pen had access to an individual outdoor range that was video-recorded continuously to obtain frequencies of individual birds' use of the ranges. Plumage condition, comb pecking wounds, skin injuries, dirtiness, toe damage, eye pathologies, footpad dermatitis, hock burns, respiratory infections, diarrhea, and walking difficulties were assessed at the end of the experiment. Statistical analysis was conducted applying generalized linear mixed models, with binomial distribution and logit link using SAS software, applying breed and ranging profile as fixed factors and their interaction, with pen as random factor. A tendency for more respiratory infections was observed in Sasso birds from each ranging profile, as compared to matching ranging profiles presented by Green-legged Partridges (outdoor-preferring: P = 0.0012; moderate-outdoor: P < 0.0001; and indoor-preferring: P = 0.0247). Indoor-preferring Green-legged Partridges tended to present more respiratory infections, as compared to the 2 other ranging profiles within the breed (outdoor-preferring: P = 0.0291; moderate-outdoor: P = 0.0448). Regardless of the breed, toe damages were more frequent in indoor-preferring birds, as compared to other ranging profiles (P = 0.017). It remains unknown whether the use of outdoor areas prevents development of welfare issues or if birds with a suboptimal welfare condition become indoor-preferring individuals.

The value of a retrospective analysis of slaughter records for the welfare of broiler chickens

The effects of transport risk factors on deaths on arrival (DOAs; %) and carcass rejections (%) on broiler chickens transported to a slaughterhouse in Southern Spain were assessed using information routinely collected at the slaughterhouse. A total of 2,284 flocks and 10,198,663 broiler chickens, transported in 2,103 commercial transports from 217 different farms to a single slaughterhouse, were studied using the information of veterinary service and slaughter records. Studied risk factors were transport condition at arrival score (good/bad) and plumage condition score (good/bad) at arrival at the slaughterhouse, mixing loads (yes/no), transport duration (min), and season of the year (spring/summer/autumn/winter). Generalized linear mixed models were used to determine the effects of risk factors and their interactions on DOA and carcass rejections. The interactive nature of risk factors affecting both variables was revealed. Mixing loads interacted with transport duration (P < 0.0001), amplifying the negative consequences of long transports on DOA. Mixing loads also interacted with transport conditions at arrival (P = 0.0005), with the impact of bad transport conditions at arrival being particularly negative in the case of mixed loads. These facts raise questions about the suitability of mixing loads both from the animal welfare and economic standpoints. Transport duration interacted with season (P = 0.0003), with the detrimental effect of long distances on DOA being particularly evident during summer and winter, which highlights the need for alternative management measures when hot or cold temperatures are foreseen during transport. Long transports also increased carcass rejections (P < 0.0001). Mixing loads and bad plumage condition exacerbated the overall, detrimental effect of autumn transports on DOA (P = 0.0084 and P = 0.0009, respectively) with respect to summer transports. Similar results were obtained for the interactions between mixing loads and transport season (P = 0.0043) and transport conditions at arrival and transport season (P = 0.0014) on carcass rejections. Overall, results highlight the value of slaughter records to produce information useful to reduce the impact of transport risk factors, improve broiler chicken welfare, and improve slaughterhouse economic results.

Risk factors for poor health and performance in European broiler production systems

BACKGROUND

Conventional broilers are currently one of the most efficient protein converters. Although decades of progress in genetic selection and feed formulation have lead to high standards of efficient broiler production, still a lot of variability is found between farms and between successive flocks. The aim of this study was to investigate risk- and/or protective factors for poor health and performance in conventional broiler-farms in Europe by developing eight multivariable linear mixed models. Three different models were used to investigate mortality (overall, first week, after first week), three models for performance variables (growth, feed conversion, European production index) and two models were related to slaughterhouse data (i.e. dead on arrival and condemnation rate).

RESULTS

Several factors related to management and housing were significantly associated with health and performance of broilers. The following factors were associated with increased mortality: floor quality, neonatal septicemia, ventilation type and other professional activities of the farmer. The factors associated with performance were chick sex, coccidiosis infections, necrotic enteritis, dysbacteriosis, light intensity adaptations, ventilation type, comparing daily flock results with previous flock results by farmer, daily check of feed and water system and type of feed. For dead on arrival three risk factors were identified i.e. daily growth, type of light adaptation and type of drinkers system. For condemnation rate seven risk factors were found, i.e. type of drinking system, daily growth, feed withdrawal time, type of ventilation, house size, septicemia after seven days and type of feed.

CONCLUSIONS

These results imply that a multifactorial approach is required with adaptations involving both improvements in management, housing, health programs and an increasing level of professionalism of the farmer in order to improve broiler performance and health.

Associations between on-farm welfare measures and slaughterhouse data in commercial flocks of turkey hens (Meleagris gallopavo)

There is a growing demand for documentation of animal welfare in meat production industry. Research on turkey welfare has mainly focused on toms at the end of production cycle, and information on the relationship between on-farm welfare and slaughterhouse recordings for turkey hens is currently lacking. The aim of this study was to investigate the relationship between routinely collected slaughterhouse data from turkey hens and their on-farm welfare measured by transect walks, to identify potential retrospective welfare indicators. The study was conducted between November 2017 and March 2018 in 20 commercial turkey flocks in Norway. On-farm welfare was evaluated using the transect walk method when the turkey hens were 11 wk old, recording the number of birds that were immobile, lame, small, featherless, dirty, sick, terminal, or dead and had visible head, tail, or wing wounds. Slaughterhouse data was provided for each flock. Univariate and multivariate linear regression models were used to investigate the associations between the variables. The results showed significant associations between several measures on farm and at slaughter. Flocks with more lameness on farm had more birds rejected at the slaughterhouse owing to leg and joint issues (P = 0.03, r = 1.01). Featherlessness and dirtiness on farm were positively associated with airsacculitis (P = 0.005; r = 0.42 and P = 0.0008; r = 0.57, respectively). The results suggest that slaughterhouse registrations may provide both practical and feasible retrospective information on the welfare of turkey hens that potentially could be implemented in future welfare assessment schemes. Further studies are needed to investigate the causal factors behind the identified relationships.

Welfare of end-of-lay hens transported for slaughter: effects of ambient temperature, season, and transport distance on transport-related mortality

The transport of end-of-lay hens for slaughter presents a particular cause for concern in relation to hen welfare due to their less robust condition. During the period of 1 January 2010 to 31 December 2017, 17,436,074 end-of-lay hens transported for slaughter in 3,144 consignments were monitored, i.e., all hens transported from Czech farms to slaughterhouses in the Czech Republic in the monitored period. The overall mortality of hens during transport for slaughter was 0.516%. A significant (P < 0.05) impact of outside temperature and month of the year on transport-related mortality was found. Lower outside temperature was connected with the increased hen mortality and vice versa. Correspondingly, more deaths of end-of-lay hens occurred in the cold winter months of January (0.717%) and December (0.695%); on the contrary, the lowest death rates were recorded in August (0.364%). Differences were also found when comparing transport-related mortality rates according to the transport distance. The lowest mortality (0.338%) was found in hens transported for distances up to 50 km; longer distances were associated with increasing (P < 0.05) death rates, with the greatest losses (0.801%) recorded for distances from 201 to 300 km. These findings document the need for increased care for end-of-lay hens during their transport for slaughter in the winter at lower outside transport temperatures, in particular below 0°C (e.g., by adequate temperature regulation in the means of transport), and of hens transported over longer distances (if the transport distance cannot be reduced).

Identifying welfare issues in turkey hen and tom flocks applying the transect walk method

In commercial conditions turkey tom and hen flocks are reared under similar housing and management conditions. However, the 2 sexes differ with regard to behavioral and physiological characteristics, and are slaughtered at different ages, resulting in different growth patterns. The rearing environment and management likely have similar effects on the welfare of both sexes reared in 1 barn, as usual in commercial flocks, but this has not previously been studied. The main aim of current study was to identify on-farm health and welfare issues of commercially reared hen and tom turkeys at 11 wk of age using the transect walk method. The study was conducted between November 2017 and March 2018 in 20 commercial turkey flocks on 16 different farms in the eastern part of Norway. On each farm, 1 barn, divided into tom and hen area, was evaluated using transect walk method. An observer walked the transects in random order and recorded the total number of birds per transect that were immobile; lame, with visible head, tail, or wing wounds; small; featherless; dirty; sick; terminal or dead. To analyze the data, we applied ANOVA and Spearman correlations in SAS software (v 9.3). The most commonly observed welfare indicators across sexes were dirty and featherless birds, and birds with tail and wing wounds. Across sexes, poor litter quality resulted in more head wounds (P < 0.05). Toms had significantly more tail wounds (P < 0.001), there were more sick birds (P < 0.01) and more terminal birds (P < 0.01) compared to hens at the same age. Several of the welfare indicators were positively correlated between the sexes, including lame, head, wing- and tail-wounded, dirty, and dead birds, suggesting similar underlying environmental causes affecting animal welfare.

Slaughter of animals: poultry

The killing of poultry for human consumption (slaughtering) can take place in a slaughterhouse or during on-farm slaughter. The processes of slaughtering that were assessed, from the arrival of birds in containers until their death, were grouped into three main phases: pre-stunning (including arrival, unloading of containers from the truck, lairage, handling/removing of birds from containers); stunning (including restraint); and bleeding (including bleeding following stunning and bleeding during slaughter without stunning). Stunning methods were grouped into three categories: electrical, controlled modified atmosphere and mechanical. In total, 35 hazards were identified and characterised, most of them related to stunning and bleeding. Staff were identified as the origin of 29 hazards, and 28 hazards were attributed to the lack of appropriate skill sets needed to perform tasks or to fatigue. Corrective and preventive measures were assessed: measures to correct hazards were identified for 11 hazards, with management shown to have a crucial role in prevention. Ten welfare consequences, the birds can be exposed to during slaughter, were identified: consciousness, heat stress, cold stress, prolonged thirst, prolonged hunger, restriction of movements, pain, fear, distress and respiratory distress. Welfare consequences and relevant animal-based measures were described. Outcome tables linking hazards, welfare consequences, animal-based measures, origins, and preventive and corrective measures were developed for each process. Mitigation measures to minimise welfare consequences were also proposed.

A combined retrospective, prospective and experimental study of Ornithobacterium rhinotracheale infection in chickens

The aim of this study was to examine the histopathological and immunohistochemical changes caused by natural and experimentally-induced Ornithobacterium rhinotracheale infection in the respiratory system of chickens. To this end, three different studies were carried out. The first was a retrospective study of 82 field cases with respiratory disorders compatible with O. rhinotracheale infection. The bacterium was immunohistochemically detected in the lungs in 48 of 82 field cases, and 50 β-haemolytic (BH) and non-haemolytic (NH) strains were isolated. In the second study, an experimental model of the disease was created using 3-week-old broiler chickens, to identify possible differences of pathogenicity between the BH and NH isolates by the intravenous (IV) and intratracheal (IT) inoculation routes (IR). The group challenged with the NH isolate showed more severe lung lesions than the group challenged with the BH isolate at 7-days postinoculation (p.i.). The 14-day p.i. groups challenged with either the BH or NH isolates by the IT or IV IR had a higher histologic grade of pulmonary and hepatic lesions and a higher total histologic grade of lesions suggesting more severe pathology with longer time of exposure. A direct association between the inoculation routes and the organs affected was shown. Finally, a slaughterhouse study was carried out from October 2014 to May 2015, in which the histologic grade of lesions was significantly higher in immunohistochemically positive for O. rhinotracheale lungs of dead-on-arrival chickens.

On-farm broiler chicken welfare assessment using transect sampling reflects environmental inputs and production outcomes

To evaluate the utility of transect sampling for assessing animal welfare in large chicken flocks, we quantified relationships between environmental inputs, welfare problems detected using transect sampling, and production outcomes. We hypothesised that environmental inputs including environmental complexity (i.e. number of environmental enrichment types provided), space allowance, underfloor heating (presence or absence), and photoperiod regimen (18 h continuous vs 16 h intermittent) would correspond to variations in welfare assessment findings, which would predict production outcomes. We conducted on-farm welfare assessment of Norwegian broiler flocks at approximately 28 days of age. We sampled four transects (rows between feeder and drinker lines) per flock to determine litter quality and the proportions of chickens with compromised welfare as indicated by visual signs of walking difficulties, illness, skin wounds and small bird size. Production outcome measures included mortality, reasons for carcass rejection at slaughter, footpad dermatitis, growth rate, feed conversion and an integrated production index. Greater environmental complexity was associated with a reduction in skin wounds and total welfare problems on the farm, lower mortality, fewer rejections due to wounds and underweight birds, and fewer rejections overall. Higher space allowances within levels of environmental complexity were associated with fewer walking difficulties and welfare problems overall, a reduction in rejections due to wounds, and a higher growth rate and production index. Underfloor heating was associated with a reduction in rejections due to leg deformity, and intermittent light was associated with lower illness and skin wound rates on the farm, and lower mortality. Furthermore, fewer welfare problems and better litter quality on the farm were associated with fewer carcass rejections at slaughter. Thus, data from transect sampling varied with environmental inputs and production outcomes, supporting the validity of transect sampling for practical, animal-based on-farm welfare assessment.

The potential of the transect method for early detection of welfare problems in broiler chickens

The potential of the transect method was tested for early detection of welfare problems associated with bird age and genetic line, litter quality, and transect location. On-farm welfare impairment and its consequences on slaughter outcomes were evaluated to test the method's predictive ability. A total of 31 commercial Ross, Cobb, and mixed RC broiler flocks were evaluated at 3, 5, and 6 wk of age. Two observers evaluated 3 transects each, simultaneously and in the same house by detecting welfare indicators including lame, immobile, sick, small, dirty, tail wounds, other wounds (head and back wounds), featherless, terminally ill, and dead birds. Increasing lame, immobile, sick, and terminally ill birds according to bird age (P < 0.001) was detected. Higher incidences of small and sick birds were detected in C and RC (P < 0.001) as compared to R flocks, whereas more dead and tail wounded were observed in RC compared to R and C flocks at week 5 (P < 0.001). Dirty incidence increased as litter quality deteriorated (P < 0.001). A higher incidence of immobile, small, sick, dirty, and dead was registered near house walls (P < 0.001). Differences across observers were detected for lame, immobile, and terminally ill birds (P < 0.001). For the observer by bird age interaction, differences were detected for dirty, tail wounds, and other wounds (P < 0.05). Pearson correlations between welfare indicators at week 3 and those at final weeks of age (P < 0.05) ranged between r values of -0.2 and 0.654 (P < 0.05). Correlations between welfare indicators and slaughter outcomes showed a relationship between flock mortality and dead on arrival, footpad dermatitis, leg problems, and illness (P < 0.05). Litter quality positively correlated with downgrades (P < 0.001). This study showed the potential of transects to detect differences in welfare indicators according to factors that effects were previously reported. It demonstrated the transect potential for detecting and predicting the consequences of welfare impairment on slaughter outcomes. This would make the transect method a useful tool for notifying and rectifying welfare deterioration as early as at 3 wk of age.

EFFECT OF PRE-SLAUGHTER CONFINEMENT STRESS ON PHYSICOCHEMICAL PARAMETERS OF CHICKEN MEAT

Abstract The effect of pre-slaughter lairage stress on biogenic amines, pH, and color with the CIELab system (where three variables L*, a*, b* are estimated: L* for lightness, a* defines redness, and b* defines yellowness) in chicken breast meat was investigated. Before slaughtering, 25 broilers were selected and divided into five groups according to lairage holding time (30 min or 3 h), day/night schedule (daylight or nighttime) and control (no lairage). After slaughtering, breasts (M. Pectoralis major) were removed, stored for 9 days at 4 °C, and analyzed every 3 days. The results showed a pH decrease during nighttime holding. Also, a three-hour pre-slaughter holding (daytime or night) resulted in high biogenic amine concentration, increase in lightness (L*), and reduction in redness (a*) during storage. Cadaverine concentration showed a rapid increase from day 6 onward. The time and schedule of chicken lairage is a pre-slaughter stress factor that affects meat quality. Based on these observations, it is recommended to slaughter chickens immediately on arrival at the processing plants.

Survey on broiler pre-slaughter mortality in a commercial abattoir of central Italy

The pre-slaughter mortality was investigated on broilers, in the Mediterranean climate condition, considering the most significant risk factors as the journey length, waiting time, season and the space allowance in cages. At first, the pre-slaughter mortality was studied considering the totality of birds and then by examining in detail three broiler categories: large, medium and small size. The average dead on arrival (DOA) recorded on the totality of birds throughout the year was 0.38% and the values obtained in winter, spring, summer and autumn were 0.52, 0.48, 0.31 and 0.22%, respectively. The mortality rate observed during the year was 0.52, 0.47 and 0.31% for large, medium and small broilers, respectively. In all three groups, the maximum values of mortality were obtained in winter, whereas the minimum ones were recorded in autumn, spring and summer for large, medium, and small size birds, respectively. The increase of journey length could cause a higher mortality rate whereas the increase of the waiting time in the facilities at controlled environmental conditions did not seem to be a risk factor, but rather a mean to reduce the number of dead animals (all P < 0.05). It is concluded that the resistance to the hostile weather conditions, long journeys and extended waiting times was strongly related with the body weight of broilers; therefore, the planning of the slaughtering activity should consider this aspect, in order to avoid animal suffering and the economic loss.

Injury and mortality in broilers during handling and transport to slaughter

Multiple factors affect the risk of broiler injury and mortality during loading, transport, and lairage. These include the physical and pathophysiological condition of broilers before loading and the type of handling procedures used. The external environmental conditions have a major influence on the risk of mortality. Combinations of high stocking density, insufficient ventilation, and high temperature and humidity pose a risk of hyperthermia. Combinations of wet conditions, cold temperature, and air movement, increase the risk of hypothermia. However, protection from cold and wet conditions involves the use of side protection that restricts the trailer ventilation that can cause heat and moisture to build up in the load, increasing the risk of hyperthermia. Modular systems reduce the risk of injury and facilitate unloading into a lairage where temperature and ventilation can be controlled. The duration of loading, transport, and lairage increases the mortality risk. Deaths can occur during each stage and interactions between the duration of the preslaughter stages, the thermal environment, fasting, ill-health, and injury can reduce the physiological capacity of the birds to maintain homoeostasis resulting in exhaustion and death. Quality control and action on the identified risk factors should reduce injury and mortality during preslaughter handling and transport.

Assessment of turkey vehicle container microclimate on transit during summer season conditions

This study evaluated the formed microclimate commercial truck transport practices effects on the turkeys' welfare by measuring Dead on Arrival (DOA) index and pale, soft, and exudative (PSE-like) meat occurrence. The experimental design was entirely randomized in a 6 × 2 factorial arrangements (two truck container compartments × six water shower groups) with birds positioned at superior front (SF), inferior front (IF), superior middle (SM), inferior middle (IM), superior rear (SR), and inferior rear (IR) and two bath treatments: with water shower (WiS) and without water shower (WoS) with eight replications for each treatment. The animals were transported for 95 min' journey from the farm to the slaughterhouse under hot-humidity conditions. The results shown herein indicated the formation of a thermal core at the inferior middle and rear truck container regions, because the heat produced by the birds and the influence of developed microclimate consisting of temperature, relative humidity, and air ventilation. The IM and IR container compartments under the WoS treatment presented the highest (P < 0.01) numbers of PSE-like meat incidence and DOA index values compared with those located at the front under WiS treatment as the consequence of the altered to birds unbearable conditions within the container microclimate in transit. The formed microclimate during the commercial transport practices under hot-humidity conditions affected the bird's welfare consequently turkey meat qualities.

Factors affecting mortality risk during transportation of broiler chickens for slaughter in Atlantic Canada

Mortality of broilers during transport and lairage before slaughter represents an economic loss to the poultry industry and a welfare issue that needs to be addressed. In Canada, broilers can be transported long distances and be exposed to environmental factors, such as cold temperatures, that can affect the percentage of dead-on-arrivals or DOAs. Slaughter plant records for loads transported over a 19-month period in 2009-2010 were examined to identify factors affecting mortality risk (% DOA) during transportation from the rearing barn to the slaughter plant. Information from 2007 loads was analysed using a multilevel linear model. Most of the variation in the mortality risk occurred at the load level rather than at the producer or barn level. There were significant effects of bird sex, age and weight, catching team, journey duration and holding barn duration on mortality risk. The following environmental risk factors increased mortality risk: cold temperatures during the journey and in the holding barn, low crate stocking density during journeys at cold temperature and increased trailer temperature when in the holding barn. The analyses identified risk factors that can be used to refine management practices to mitigate some of the mortality risk. Increased mortality in some loads was associated with environmental conditions that caused deaths from hypothermia, whereas in other circumstances, some deaths likely occurred from hyperthermia. The climatic conditions in Atlantic Canada were responsible for significant risk factors that affected the mortality risk. Although refinement of the management practices described in this study, such as reduced journey and lairage durations, and increased crate stocking density can mitigate some of the mortality risk, the extreme cold conditions experienced during some parts of the year exceeded the capacity of the systems of transportation used to provide environmental conditions that minimise mortality.

Influence of hot exposure on 12-week-old turkey hen physiology, welfare, and meat quality and 16-week-old turkey tom core body temperature when crated at transport density

The influence of hot conditions on 12-week-old turkey hens and 16-week-old toms while crated at transport density was evaluated. Forty-eight hens and 48 toms (8 birds per flock × 3 flocks × 2 humidity levels) were used in neutral treatments (trt; 20°C), and 16 hens and 16 toms (8 birds per flock × 1 flock × 2 humidity levels) were used in the hot trt (35°C). Birds were placed in crates at a transport stocking density of approximately 83 kg/m2, then inside a pre-conditioned chamber for 8 hours. Live shrink, core body temperature (CBT), heterophil/lymphocyte (H/L) ratio, and breast and thigh pH and color were recorded. Differences were declared significant at P ≤ 0.05. Live shrink after exposure to the 35°C trt (4.92%) was greater (P < 0.0001) than when birds were exposed to 20°C (1.48%). The 35°C trt (P < 0.0001) had higher Δ CBT (final minus initial) compared to the 20°C trt. The 35°C trt also caused higher (P < 0.0001) H/L ratio, 4.07 vs. 1.57 for the 20°C trt. Breast (P = 0.0110) and thigh pH levels (P < 0.0001) measured 27 h postmortem were lower for the 35°C trt at 5.64 and 5.73 compared to the 20°C trt at 5.70 and 5.92, respectively. Breast meat from birds exposed to 35°C was darker (P < 0.0001), while the color of thigh meat was unaffected. Toms quickly became distressed in the hot conditions, forcing those tests to be aborted. Only CBT data were analyzed. The CBT increased at a mean rate of 0.09°C/min for hens at both RH levels, while the CBT of toms increased at 0.12 and 0.18°C/min when exposed to 35°C, 30%; and 35°C, 80%, respectively. Exposure to hot temperatures caused higher CBT, greater live shrink, and greater H/L ratio. Toms were more greatly affected than hens to the hot trt, with CBT increasing at a greater rate.