Broiler Welfare Research Articles

Reducing stocking density benefits behaviour of fast- and slower-growing broilers

The broiler industry has come under sustained pressure from welfare organizations to improve broiler welfare. Breed and stocking density are important factors for broiler welfare and are often specified as criteria for higher welfare systems. However, it remains unknown how slower-growing broilers respond to a reduction in stocking density with regard to their behaviour, and whether this response differs from fast-growing broilers. Therefore, we compared fast- (Ross 308) and slower-growing broilers (Ranger Classic) housed at 4 different stocking densities (24, 30, 36 and 42 kg/m2, based on slaughter weight) with regard to their behaviour, responses to behavioural tests (i.e., novel object (NO), human approach (HA) and free-space (FS) test) and enrichment use at 4 target body weights (TBW’s, 0.4, 1.1, 1.7 and 2.1 kg). The experiment had a 2 × 4 factorial design with 4 replicates (pens) per treatment (total of 32 pens). Thinning (15%) was done in a 50/50 male/female ratio at 38 (Ross 308) and 44 (Ranger Classic) days of age (estimated body weight of 2.2 kg). We hypothesized that slower-growing broilers would respond more strongly to a reduction in stocking density with regard to their behaviour. As slower-growing broilers are more active and show more comfort and foraging behaviours, it is expected that with increasing space they will respond with a larger increase in these types of behaviours compared to fast-growing broilers. Contrary to our hypothesis, hardly any interactions between breed and stocking density were found, indicating that fast- and slower-growing broilers showed similar responses to a reduction in stocking density. Broilers housed at lower stocking densities (24 and/or 30 kg/m2) showed more comfort and foraging behaviour, and showed more frolicking, running and sparring in the FS test compared to those housed at higher stocking densities (36 and/or 42 kg/m2). Slower-growing broilers showed less ingestion, more locomotion, standing, comfort and foraging behaviour, made better use of the enrichment by sitting on the bale, and more slower-growing broilers approached a human and NO compared to fast-growing broilers. In conclusion, reducing stocking density positively affected performance of comfort, foraging and play behaviours, indicating improved welfare. Slower-growing broilers showed more locomotive, comfort and foraging behaviours, less fear and a better use of enrichments, suggesting improved welfare compared to fast-growing broilers. Thus, reducing stocking density and using slower-growing broilers would benefit broiler welfare, where combining both would further improve broiler welfare with regard to their behaviour.

Use of black soldier fly larvae to improve the welfare and behaviour of broilers

Use of black soldier fly larvae to improve the welfare and behaviour of broilers

Poultry Meat Quality in Antibiotic Free Production Has Improved by Natural Extract Supplement.

Simple SummaryFarm sustainability is a key factor in animal production. In the recent years, the consumers’ demand for products of animal origin coming from production chains certified for animal welfare has increased. Moreover, the institutions have limited the antibiotic use to prevent the antibiotic resistance. For these reasons, antibiotic-free production chains are emerging. The search for sustainable nutritional approaches able to strengthen animal health and enhance product quality is essential. Natural extracts and seaweed contain several bioactive compounds capable of enhancing animal health and product quality. The present study investigates the effect of dietary supplementation with polyphenols and seaweed mixtures on meat quality parameters in Hubbard slow growth chicken in antibiotic-free production. The present data suggest that dietary supplementation with polyphenols and seaweed mixture increased breast muscle protein content and protect the muscle from oxidative processes, enhancing poultry meat quality parameters.Modern consumers are conscious of the relationship between meat quality and animal welfare. Today, slow-growing chickens are associated with a higher broiler welfare. The present work aims to evaluate the effect of dietary natural extract supplementation with polyphenols and seaweed mixtures (PPE) on breast and thigh muscles quality parameters in Hubbard JA57 slow growth chicken in antibiotic-free production. Five hundred Hubbard female chickens (250 from control and 250 from experimental group) were housed on floor pens (10 pens/treatment, 25 birds/pen) and assigned to two experimental groups: a control group (CON) receiving a commercial diet and another group receiving the same diet supplemented with 0.3% of polyphenols and seaweed mixtures (PPE). Dietary supplementation with PPE did not affect (p > 0.05) growth performances. The breast pH tended to be lower (p = 0.062) in PPE groups. The protein content of breast muscles resulted higher in PPE samples (p < 0.05) than controls. The thigh muscles from PPE group showed a lower (p < 0.05) malondialdehyde content than CON during refrigerated storage. In conclusion, the PPE supplement improves breast muscle protein content and oxidative stability of thigh muscle. This feeding practice is suggested to enhance the nutritional and technological parameters of meat Hubbard slow growth chicken in antibiotic-free production.

8 Prediction of Culling and Mortality Risks in Group-Housed Broilers Using Machine Learning Methods Trained with Time-Series Data of Feeding Behavior Traits

Abstract In this study, we investigated the performance of different machine learning (ML) methods for predicting withdrawing events (culled or dead animals) according to feeding behaviors (FB) time series. The raw data comprised a total of 1,492,482 daily observations for six FB traits from 55,400 birds allocated into 88 trials. After data editing, the overall class distribution was 17:1 (44,352 healthy animals and 2,689 culled or dead). The event classification (0 or 1) was performed one day in advance, by treating healthy birds randomly as control groups for each day. The FB daily trends were used for extracting 21 time-series features per trait, generating a structured feature dataset (day before the event + 126 time-series features). The trained ML algorithms were the gradient boosting machine (GBM), multilayer perceptron neural network (MLP), naïve Bayes (NB), random forest (RF), and support vector machine (SVM). The models were compared based on the area under the ROC (AUC) and precision-recall (AUPRC) curves, computed with 20-fold cross-validation. The performance metrics ranged from 0.76 to 0.85 for AUC and from 0.32 to 0.48 for AUPRC, so that models achieved considerable superior performance than that expected for a random classifier (0.50 for AUC and 0.06 for AUCPR). The better classifier in terms of AUC was the RF (0.85±0.02), although not statistically different from the average performance obtained with the GBM and SVM (0.84±0.02 in both cases). The MLP achieved the greatest AUPRC (0.48±0.05), while the NB performed poorly considering this criterion (0.32±0.02), indicating that a low precision-recall gain is expected for this model. Broiler barns presenting a critical number of animals with high-risk scores could be indicative of a disease outbreak or management failures. Hence, the proposed approach offers a potential tool for real-time monitoring of health status and welfare in broilers.

Age and sex related changes in fattening performance, dermatitis, intestinal histomorphology, and serum IgG level of slow- and fast-growing broilers under the intensive system.

Due to consumers' concerns about broiler welfare, slow-growing broilers (SGB) have also been used in production. Fast-growing broilers (FGB) reach slaughter weight earlier the slow growing. This study was aimed to determine the sex-related changes in fattening performance, dermatitis, intestinal histomorphology, and serum IgG level of SGB and FGB under the intensive system during the 10weeks. A total of 336 one-day-old broilers were distributed into four equal groups (FGB-female, FGB-male, SGB-female, and SGB-male) consisting of a 2 × 2 factorial design. The main factors were genotype (FGB and SGB) and sex (female and male). Each treatment had 6 duplicates consisting of 14 broilers. They were placed on the litter pens. The experiment lasted 10weeks. The body weight, body weight gain, feed consumption, and feed-to-gain ratio were determined weekly during the experiment. One broiler close to the average body weight from each pen (6 broilers in the group) has been slaughtered each week and intestinal histomorphology was determined. Additionally, IgG levels in the blood and dermatitis were determined. While the period in which the body weight gain was the highest in the FGB was up to 6week of age, this period lasted until the 7week of age in the SGB (P < 0.001). It has been determined that FGB have the best feed efficiency ability during both 6weeks of fattening period and 10weeks of fattening period (P < 0.001). The difference between the sex in terms of the feed efficiency appeared after the age of 4weeks and this difference continued until the age of 9weeks (P < 0.01). It was determined that villus height, crypt depth, and the ratio of villus height to crypt depth in the jejunum region were higher in FGB from the age of 1week than in SGB (P < 0.05). It was observed that the incidence of dermatitis increased in the FGB (P < 0.001). It has been determined that the genotype (P < 0.01) and period (P < 0.001) were effective according to the IgG level. These results indicate that 7 and 8weeks can be considered important periods in terms of economic efficiency in SGB and FGB reared for 10weeks under the same management systems and it was observed that both genotypes would be more susceptible to diseases at the age of 6weeks.

Effects of light intensity on growth performance, blood components, carcass characteristics, and welfare of broilers.

This study investigated the effects of light intensity on growth performance, blood components, eye condition, and carcass characteristics of broiler chickens. Three hundred and fifty-two 1-day-old male chicks were assigned to one of four treatments (four repetitions per treatment, 22 birds per repetition) and reared in a floor pen for 5 weeks. From the second week, chicks were reared under four different levels of light intensity (5, 20, 35, and 50 lx) and the lighting duration was maintained at 18-hours light : 6-hours dark (18L : 6D). The feed intake and body weight were measured weekly. At 35 days of age, 12 birds per treatment were randomly selected for blood sampling, eye measurement, and carcass analysis. There were no significant differences in body weight gain, feed intake, and feed conversion ratio among treatments. Triglyceride levels in the serum were significantly higher in the 5 lx treatment, and creatinine was significantly lower in the 5 lx treatment (p < 0.05). The heterophil : lymphocyte ratios decreased significantly as light intensity increased (p < 0.05); however, other blood cell compositions were not affected by light intensity. Interleukin-6 content was significantly higher in the 5 lx treatment than in other treatments (p < 0.05), but the content of tumor necrosis factor-α was not significantly different among treatments. Serum corticosterone concentration was significantly higher at 5 lx than at 20, 35, and 50 lx (p < 0.05). The corneal diameter was the highest in 5 lx treatment (p < 0.05), and tended to increase as the light intensity decreased. Other eye parameters were not significantly different among treatments, but displayed a tendency to increase as the light intensity decreased. Carcass yield and part yields were not affected by light intensity. Meat quality parameters (pH, color, cooking loss, and water-holding capacity) did not show significant difference among the treatments. The results indicate that a light intensity of 5 lx may increase physiological stress or have a negative effect on broiler welfare, even if the performance and carcass characteristics are not affected. Therefore, a light intensity of 20 lx or above is recommended considering both the growth performance and welfare of broilers.

The impact of changing toward higher welfare broiler production systems on greenhouse gas emissions: a Dutch case study using life cycle assessment

In the Netherlands, the Dutch Retail Broiler (DRB) and Better Life one Star (BLS) production systems have been introduced with the aim to improve broiler welfare. Simultaneously, retailers set targets for reduction of greenhouse gas (GHG) emissions in the whole broiler production chain. The GHG emissions of DRB and BLS may differ from conventional systems because of differences in slaughter age, feed intake, and diet composition. The aim of this study was to estimate GHG emissions of the conventional, DRB, and BLS production systems. A deterministic, spreadsheet based model was developed that included the breeder, hatchery, and broiler farm stages. First, the model calculates feed intake of different diets and energy use, based on performance objectives and literature. Selection of feed ingredients for the different types of diets was based on least cost formulation with nutritional constraints for each diet. Second, GHG emissions were estimated from cradle to broiler farm gate for processes along the broiler production chain by using life cycle assessment, and expressed as kg CO2-equivalents per kg live weight (kg CO2-eq/kg LW). Results showed that BLS (3.55 kg CO2-eq/kg LW) had lower GHG emissions compared to conventional (3.65 kg CO2-eq/kg LW) and DRB (3.98 kg CO2-eq/kg LW) at the broiler farm gate. Emissions from land use change (LUC) from feed production, mainly from soybean products, had highest impact on total GHG emissions (>50%) for the systems and these soybean products had the lowest inclusion in the diets of the BLS production system. Sensitivity analyses showed that variation in slaughter weight and feed intake could result in overlap of GHG emissions between systems. When soybean products were sourced from a country with low LUC emissions, conventional (1.37 kg CO2-eq/ kg LW) had the lowest GHG emissions and BLS (1.79 kg CO2-eq/kg LW) the highest. This study showed that origin of and including or excluding LUC emissions from soybean production results in different conclusions for achieving the GHG emissions reduction targets set by retailers.

Does feeding more phases reduce ammonia concentrations from broiler litter?

We compared a 3- and 5-phase feeding program in terms of ammonia concentrations measured at litter level, litter composition and quality, nitrogen (N) utilization, performance, welfare, and meat deposition in broilers. A total of 744 Ross 308 male broilers was divided into 2 treatments, each with 6 replicates. The 3-phase diets were formulated to CP and digestible lysine contents of 205 and 11.5 g/kg (0 to 9 d), 195 and 10.8 g/kg (9 to 24 d), and 183.3 and 10.15 g/kg (24 to 39 d), respectively. The 5-phase diets had additional phases from 17 to 24 d and 32 to 39 d with CP and digestible lysine contents of 188 and 10.4 g/kg and 177 and 9.8 g/kg, respectively. Feeding 5 phases reduced the NH3 concentrations at litter level by 37.95% and 20.81% at 23 (P < 0.05) and 37 d of age (P < 0.05), respectively. There was a tendency for a lower litter total ammoniacal nitrogen concentration for the 5-phase treatment than the 3-phase treatment at 24 and 39 d of age (P < 0.1 for both). Total N concentration of the litter also tended to be lower for the 5-phase treatment at 39 d of age (P < 0.1). The lower NH3 coincided with a lower average litter pH at 24 and 32 d of age (P < 0.05 for both). Birds fed the 5-phase treatments had a lower incidence of foot lesions at 24 d of age (P < 0.001). Performance as well as carcass yield could be maintained, except for FCR, which was higher for the 5-phase treatment between 17 and 24 d of age and the overall period (P < 0.05 and < 0.001, respectively). The impact of the 5-phase treatment regarding the utilization of N (digestibility, excretion, and retention) was less clear, however the NH3 volatilized from the litter was significantly reduced. Feeding 5 phases may therefore potentially reduce the NH3 emitted from broiler houses which has several environmental and health benefits. Although the 5-phase treatment resulted in a significant decrease in feed efficiency, growth performance and meat deposition were maintained.

Seeing is caring – automated assessment of resource use of broilers with computer vision techniques

Routine monitoring of broiler chickens provides insights in the welfare status of a flock, helps to guarantee minimum defined levels of animal welfare and assists farmers in taking remedial measures at an early stage. Computer vision techniques offer exciting potential for routine and automated assessment of broiler welfare, providing an objective and biosecure alternative to the current more subjective and time-consuming methods. However, the current state-of-the-art computer vision solutions for assessing broiler welfare are not sufficient to allow the transition to fully automated monitoring in a commercial environment. Therefore, the aim of this study was to investigate the potential of computer vision algorithms for detection and resource use monitoring of broilers housed in both experimental and commercial settings, while also assessing the potential for scalability and resource-efficient implementation of such solutions. This study used a combination of detection and resource use monitoring methods, where broilers were first detected using Mask R-CNN and were then assigned to a specific resource zone using zone-based classifiers. Three detection models were proposed using different annotation datasets: model A with annotated broilers from a research facility, model B with annotated broilers from a commercial farm, and model A+B where annotations from both environments were combined. The algorithms developed for individual broiler detection performed well for both the research facility (model A, F1 score &amp;gt; 0.99) and commercial farm (model A+B, F1 score &amp;gt; 0.83) test data with an intersection over union of 0.75. The subsequent monitoring of resource use at the commercial farm using model A+B for broiler detection, also performed very well for the feeders, bale and perch (F1 score &amp;gt; 0.93), but not for the drinkers (F1 score = 0.28), which was likely caused by our evaluation method. Thus, the algorithms used in this study are a first step to measure resource use automatically in commercial application and allow detection of a large number of individual animals in a non-invasive manner. From location data of every frame, resource use can be calculated. Ultimately, the broiler detection and resource use monitoring might further be used to assess broiler welfare.

A review of heat stress in chickens. Part II: Insights into protein and energy utilization and feeding.

With the growing global demand for animal protein and rising temperatures caused by climate change, heat stress (HS) is one of the main emerging environmental challenges for the poultry industry. Commercially-reared birds are particularly sensitive to hot temperatures, so adopting production systems that mitigate the adverse effects of HS on bird performance is essential and requires a holistic approach. Feeding and nutrition can play important roles in limiting the heat load on birds; therefore, this review aims to describe the effects of HS on feed intake (FI) and nutrient digestibility and to highlight feeding strategies and nutritional solutions to potentially mitigate some of the deleterious effects of HS on broiler chickens. The reduction of FI is one of the main behavioral changes induced by hot temperatures as birds attempt to limit heat production associated with the digestion, absorption, and metabolism of nutrients. Although the intensity and length of the heat period influences the type and magnitude of responses, reduced FI explains most of the performance degradation observed in HS broilers, while reduced nutrient digestibility appears to only explain a small proportion of impaired feed efficiency following HS. Targeted feeding strategies, including feed restriction and withdrawal, dual feeding, and wet feeding, have showed some promising results under hot temperatures, but these can be difficult to implement in intensive rearing systems. Concerning diet composition, feeding increased nutrient and energy diets can potentially compensate for decreased FI during HS. Indeed, high energy and high crude protein diets have both been shown to improve bird performance under HS conditions. Specifically, positive results may be obtained with increased added fat concentrations since lipids have a lower thermogenic effect compared to proteins and carbohydrates. Moreover, increased supplementation of some essential amino acids can help support increased amino acid requirements for maintenance functions caused by HS. Further research to better characterize and advance these nutritional strategies will help establish economically viable solutions to enhance productivity, health, welfare, and meat quality of broilers facing HS.

The Effects of Providing Outdoor Access to Broilers in the Tropics on Their Behaviour and Stress Responses.

Simple SummaryThe effects of outdoor access for broilers have been tested under temperate conditions, where free-range systems have begun to be widely used. However, under tropical conditions, where the birds may be heat-stressed outside, the benefits of providing a free-range area may be less evident. We compared whether access to an outdoor area improved behavior and several physiological welfare indicators of broilers at two stocking densities in a tropical environment. There were no major effects of outdoor access on broiler behavior, except that resting was reduced by providing outdoor access to older birds and those at low stocking densities inside. However, outdoor access increased heterophil numbers in summer, but not in winter, which may indicate heat stress. We concluded that the effects of outdoor access on the welfare of broilers in the tropics are dependent on season and stocking density.The effects of outdoor access, stocking density, and age on broiler behavior, stress, and health indicators in a tropical climate were assessed over two seasons, winter and summer. Two hundred and forty Cobb500 male chickens were allocated to one of four treatments, with six replicates of ten birds in each: low stocking density indoors with outdoor access (LO); high stocking density indoors with outdoor access (HO); low stocking density indoors without outdoor access (LI); and high stocking density indoors without outdoor access (HI). Scan sampling was used to record their behavior both indoors and outdoors. At 28 and 42 days old, blood samples were obtained to determine the heterophil to lymphocyte (H/L) ratio. At 42 days old, chickens were culled and inspected for footpad dermatitis (FPD), and bone quality was examined. Their spleens and bursas of Fabricius were collected and weighed, relative to carcass weight (RW). A factorial analysis was used to test the effects of season (winter or summer), outdoor access (with or without), stocking density (low: 5 animals/m2 or high: 10 animals/m2), and age (28 or 42 days) on the behavior and stress and health indicators. There were no major effects of providing outdoor access on behavior, except that resting was reduced by providing outdoor access to older birds and those at low stocking densities inside. Resting was also greater in indoor and high-density treatments during winter. The bursa of Fabricius was heavier in summer in outdoor birds. The tibia bones were shorter in the outdoor birds. Heterophil numbers were greater in the outdoor treatments in summer but not in winter. These results indicate that outdoor access can increase activity in some situations, and potentially increase bone strength, but it may also increase the risk of stress, particularly heat stress in summer.

Health-Based Welfare Indicators and Fear Reaction of Slower Growing Broiler Compared to Faster Growing Broiler Housed in Free Range and Conventional Deep Litter Housing Systems

ABSTRACT This study investigated the welfare of a slow-growing broiler with a commercially available fast-growing breed housed in a free-range and conventional deep litter housing system. There were four main groups (2 genotypes x 2 housing systems), and each main group consisted of 5 replicates. Ante-mortem and postmortem health-based welfare indicators wıth fear reactıons and distribution of severity of them in 200 male chicks (100 slow growing, 100 fast growing) were investigated. All welfare parameters investigated were found to be significantly different between both broiler genotypes. No significant differences were detected for all broiler welfare parameters between the two housing systems. There were significant genotype x housing system interactions for breast dirtiness and feather cover of the birds (P < 0.001). In conclusion, it can be said that slow-growing broilers express more health-based indicators of positive welfare, and they might be more suitable for free-range broiler meat production. Planning further studies especially in commercial conditions that take into account economic efficiency as well as animal welfare and growth performance would be very beneficial.

Age-related effects of feeder space availability on welfare of broilers reared to 56 days of age part 1: biochemical, enzymatical, and electrolyte variables

Consumer concern about rapid growth and increased production efficiency is perceived to negatively impact the welfare of the animal. This study investigated the effects of feeder space availability on welfare of broiler chickens reared to 56 d of age on biochemical, enzymatical, and electrolyte parameters. The study was a randomized complete block design. In each of the 2 trials, a total of 1,440 one-day-old Ross × Ross 708 chicks (straight-run) were obtained from a commercial hatchery. Chicks were equally and randomly allocated to 32 pens based on feeder space treatment. The 4 feeder space treatments were 2.3 cm/bird with one feeder per pen and 2.3, 4.6, and 6.9 cm/bird with 3 feeders per pen and retain uniform bird:feeder floor space, 3 feeders were installed in each pen, except for the single feeder pen. Blood samples (3 mL) were collected from the brachial wing vein of 3 birds per pen on d 27 and 55. The collected blood samples were centrifuged for plasma to determine the electrolyte levels, biochemical concentrations, and enzyme activities. Results show that only uric acid was affected by feeder space while age had significant effects on most examined variables. Plasma corticosterone and glucose were not affected by feeder space and age, indicating absence of physiological stress. In conclusion, expanding feeder allowance does not enhance welfare of broilers reared to 56 d of age.

Effects of common litter types and their physicochemical properties on the welfare of broilers.

Background and Aim:In broiler production, the poor quality litter not only may lead to a deterioration of the welfare status but also negatively affect carcass quality, overall health and growth performance, which may result in economic losses. The effects of litter types on the welfare of broilers are known but the effects of their characteristics have been little studied. This study aimed to evaluate correlations between welfare parameters of broilers and physicochemical characteristics of five common litter types.Materials and Methods:Over 42 days, 600 (Cobb 700) male broiler chicks were placed within 30 pens (each 2 m2) at a density of 10 birds/m2. The experiment included five treatments with six replicates per treatment. The following litter (or bedding) materials were examined: Standard quality straw, low-quality straw, wood shavings (WS), sawdust, and crop residues. Footpad condition, hock burns, and plumage cleanliness, as well as litter condition, were scored according to previously developed point scale systems. Litter quality was evaluated according to pH level, moisture, water-holding capacity, and ammonia content.Results:No significant differences were found among litter types in terms of pH, moisture content, or ammonia levels. WS had a significant positive effect on footpad health and plumage cleanliness. However, hock burn was not affected by different bedding types. The severity of pododermatitis was negatively correlated with litter type (r = −0.78; p < 0.001) and positively correlated with the litter scores (r = 0.67; p < 0.001). However, contact dermatitis observed (pododermatitis and hock burn) was not correlated with any of the physicochemical parameters we studied. Meanwhile, we observed a correlation between footpad lesions and hock burn (r = 0.45; p < 0.05), and between footpad lesions and plumage cleanliness (r = 0.59; p < 0.01).Conclusion:For all litter types examined, contact dermatitis was not correlated with any of the physicochemical components we studied. There were, however, significant correlations between litter type and footpad lesions, as well as between footpad dermatitis and hock burns.

Lighting programme as a management tool for broilers raised without antibiotics – impact on productivity and welfare

ABSTRACT 1. This study investigated the impact of photoperiod on the productivity and welfare of broilers reared without antibiotics (RWA). 2. A total of 8,064 mixed sex Ross 308 broilers were allocated to two trials. Lighting treatments were 14L:10D, 17L:7D, 20L:4D or 23L:1D. 3. Significance defined when P ≤ 0.05 and trends noted when P ≤ 0.10. Highest body weights and feed consumption were found in the 4D treatment. Longer dark periods resulted in improved feed conversion. Uniformity was improved with 1D. 4. Heterophil/lymphocyte ratios were highest in birds reared on 1D. Longer photoperiods negatively impacted gait and footpad scores. Birds spent more time performing feeding behaviours under longer photoperiods. Birds reared under 1 and 10D spent more time standing while those under 4 and 7D spent more time preening. Birds raised on 4D spent more time environmental pecking, while object pecking occurred more under 10D. Condemnations were lowest in birds reared under 7D. 5. In conclusion, rearing RWA broilers on longer photoperiods negatively impacted welfare, as indicated by poorer mobility, higher stress, more severe footpad lesions, and altered behaviour.

Differences and variation in welfare performance of broiler flocks in three production systems

There is a trend toward broiler production systems with higher welfare requirements, that use slower growing broiler strains, apply a reduced stocking density and provide environmental enrichment. Although these separate factors each contribute to increased broiler welfare, there is little information on their combined effect on broiler welfare under commercial conditions, and on the variation in welfare performance of flocks within production systems. The aim of this study was to compare the welfare performance and the between-flock variation in welfare of 3 Dutch commercial broiler production systems differing in welfare requirements: Conventional (C), Dutch Retail Broiler (DRB) and Better Life one star (BLS). We applied a welfare assessment method based on the Welfare Quality broiler assessment protocol, in which we used 5 animal-based welfare measures collected by slaughterhouses and hatcheries (mortality, footpad dermatitis, hock burn, breast irritation, scratches), and 3 resource- or management-based measures (stocking density, early feeding, environmental enrichment). Data were collected for at least 1889 flocks per production system over a 2-year period. To compare the different measures and to generate an overall flock welfare score, we calculated a score on a scale from 0 to 100 (bad-good) for each measure based on expert opinion. The overall flock score was the sum of the scores of the different welfare measures. The results showed that with increasing welfare requirements, a higher total welfare score was found across production systems (BLS > DRB > C; P < 0.0001). Regarding individual measures, C generally had lower (worse) scores than BLS and DRB (P < 0.05), except for scratches where C had highest (best) score (P < 0.001). Both welfare measure scores and the total welfare score of flocks showed large variation within and overlap between systems, and the latter especially when only the animal-based measures were included in the total flock score. Total flock score ranges including animal-based measures only were: 112.1 to 488.3 for C, 113.0 to 486.9 for DRB, 151.3 to 490.0 for BLS (on a scale from 0 [bad]–500 [good]), with median values of 330.8 for C, 370.9 for DRB, and 396.1 for BLS respectively. This indicates that factors such as farm management and day-old chick quality can have a major effect on the welfare performance of a flock and that there is room for welfare improvement in all production systems.

Farmers’ Perception on the Welfare of Broiler Chickens in Smallholder Production Systems in Kiambu County, Kenya

In Kenya, commercial broiler production is growing rapidly due to increasing demand for poultry meat resulting in higher incomes for farmers. Due to this increase in demand, broiler chicken production is increasingly becoming intensive where chickens are overstocked in deep litter systems subjecting the birds to suffering perpetuated through burns on their shanks and breasts with constant footpad lesions, thus compromising their welfare. This study was conducted to determine the farmers’ attitudes towards the welfare of broiler chickens in smallholder production systems in Kiambu County, Kenya. A total of 120 farmers were randomly chosen for the study consisting of 42 and 78 respondents from Kikuyu and Kabete subcounties, respectively. A semistructured questionnaire was used to interview the farmers on their knowledge, attitudes, and practices in regard to broiler welfare. The results of this study indicated that most farmers (74%) in Kikuyu and Kabete subcounties had knowledge about broiler welfare. Media, hatcheries, agrovet centres, and extension agents were the main sources of information on broiler welfare to farmers at 61%, 40%, 38.8%, and 31.5% respectively. Farmers perceived that good feeding (88%), good health (83%), suitable housing (82%), and appropriate behaviour (48%) were very important indicators of broiler chicken welfare. Gumboro (infectious bursal disease) and new castle disease (NCD) were prevented through vaccination by most farmers (91%), while coccidiosis was controlled through cleaning and disinfection of broiler sheds and equipment as well as treatment of sick birds with coccidiostat. In conclusion, farmers’ perception on broiler welfare has a bearing on the performance of broiler chickens.

Respiratory health of broilers following chronic exposure to airborne endotoxin

In and around poultry farms, high concentrations of endotoxins are found that have a negative impact on the health of farmers and local residents. However, little is known about the effects of chronic exposure to endotoxins on the health of poultry. The aim of this study was to identify effects of chronic exposure to airborne endotoxins (E. coli LPS) on the immune system, respiratory tract, disease susceptibility and welfare of broilers. Effects of high (HE) and low endotoxin (LE) concentrations on natural antibody titers (NAb), performance and behavior of broilers were determined. After treatment with a respiratory virus infection, infectious bronchitis virus (IBV), mRNA expression of cytokines and Toll-like receptor (TLR) 4 in the lung, tracheal ciliary activity and lesions in the respiratory tract were determined. Endotoxin affected the immune system and respiratory tract, where HE broilers tended to have lower IgM NAb binding Phosphorylcholine-conjugated to Bovine Serum Albumin, and higher interferon (IFN)-α mRNA expression and more lesions in the nasal tissue compared to LE broilers. Furthermore, HE broilers had higher TLR4 mRNA expression compared to LE broilers. However, endotoxin did not affect NAb levels binding Keyhole Limpet Hemocyanin, IFN-β and interleukin-10 mRNA expression, IBV replication or lesions in the lung and trachea. HE and LE broilers further had similar body weight, but HE broilers showed numerically more passive behavior compared to LE broilers. In conclusion, chronic exposure to high airborne endotoxin concentrations affects components of the immune system and respiratory tract in broilers and could therefore influence disease susceptibility.

Animal Welfare Assessment: Quantifying Differences Among Commercial Medium and Fast Growth Broiler Flocks

A combined welfare assessment protocol, including indicators from the Welfare Quality® and AWIN® EU funded projects, was tested on commercial fast and medium growth commercial broiler flocks to determine differences in their assessments as measured with the used of animal welfare indicators. Ten commercial fast (Ross 308, Cobb 500, or a mix of both) and 10 medium growth (Hubbard JA × Ross 308), mixed sex commercial flocks were assessed at 32 and 48 days of age, respectively. Two observers simultaneously collected data on each flock. Observations included transect walks on central and wall areas to assess the AWIN® welfare indicators, bedding quality, environmental parameters and positive behaviors, all of them collected with the i-WatchBroiler app. According to the WQ protocol, welfare assessment indicators including the human avoidance tests, gait score, body weight and hock burns were also measured on each flock. Novel object tests were also carried out. The results of the study show that fast growth flocks had a higher incidence of welfare issues shown by the higher percentage of immobile, lame, sick, featherless, and tail wounded birds. Positive behaviors such as play fighting, wing flapping and running were more frequently observed in medium growth flocks on central locations, while fast growth flocks had a more limited expression of such behaviors. Fast growth flocks also had worse gait scores. Medium growth flocks expressed a different response to behavioral tests depending on the house location, likely attributable to their better mobility and welfare state, and also to the smaller stocking densities at which they were housed, while on the other hand the behavior of fast growth broilers during tests was similar regardless house location, being likely affected by mobility problems and the higher stocking density specific to their management. These results provide quantitative evidences on the differences in animal welfare assessment outcomes in fast and medium growth broilers. Nevertheless, results also suggest that some of the test responses were associated with the physical state and movement ability of the birds and house location that limit their response capacity. Such limitations should be considered when interpreting animal welfare assessment outcomes. These results add to previously published scientific evidences showing the potential of the method and app technology for practical on-farm broiler welfare assessment, including positive indicators, with farmers, technical personnel, certification bodies or scientist as potential end-users.

Machine Learning Model for Assuring Bird Welfare during Transportation

Bird welfare and comfort is highly impacted by extreme environments, including hot/cold temperatures, relative humidity, and heat production within the coops during loading at the farm, transportation, and holding at the processing plants. Due to the complexity of the multiphysics phenomena involving fluid flow, heat transfer, and multispecies mixtures (humidity) within the coops, machine learning models may be helpful to evaluate broiler welfare under various environments. Machine learning techniques (Artificial Neural Networks and Bayesian Optimization) were applied to estimate the desired parameters required to ensure broiler welfare inside the coops. Artificial Neural Networks (ANNs) were trained with the results of Computational Fluid Dynamics (CFD) simulations for various ranges of inputs related to the microenvironment. Input variables included air velocity, broiler heat production, ambient temperature, and relative humidity. The Output variable was the Enthalpy Comfort Index (ECI), which is a measure of the bird welfare. The trained networks were then analyzed using Bayesian Optimization (BO) for the inverse mapping of ANNs and to predict the range of acceptable input parameters for a desired output, i.e., ECI in the comfort level. Results indicate that reducing the broilers heat production inside the coop along with increasing fan velocity enhances the broiler welfare and the thermal microenvironment. The BO developed in this study provide the microenvironmental parameters to estimate the bird welfare that is comfortable.