Hens In Cages Research Articles

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

This study was designed to investigate the effects of different housing systems on production performance, egg quality and welfare in laying hens. One hundred and twenty 42-week-old "Atak S" laying hens, purchased from a manufacturing company, were randomly assigned to 4 housing systems: conventional cages, furnished cages, deep-litter system and free-range. Each system housed 30 hens, which were kept in these systems for 6 weeks. Parameters regarding production performance, egg quality, plumage condition scores and tonic immobility were assessed at the end of the housing period. Egg production and egg mass were lower in cage-free rearing systems than in caged systems. Mean egg weight in free-range hens, and albumen height and Haugh unit in deep-litter hens, were lower than in other housing systems. Eggshell weight in hens housed in furnished cages was greater than in free-range hens, while eggshell strength was better compared to that of hens in conventional cages. The housing system did not impact fearfulness; however, the deep-litter housing increased the sensitivity to touch or capture. Whole body and regional plumage condition scores of free-range hens elicited more favourable results than those kept in conventional cages. Because the plumage condition indicates welfare, the results proved the superiority of free-range over conventional rearing regarding welfare. Concerning the parameters, such as egg production, animal welfare and fear level, overall data revealed the pros and cons of all housing systems investigated. We consider that this study's findings might contribute to the researchers and breeders seeking alternative housing for laying hens.

Occurrence of Salmonella spp. in flocks of laying hens in different housing systems in eastern Croatia from 2020 to 2023

Human Salmonella infections are often associated with the consumption of infected eggs and egg products. Therefore, knowing the prevalence of Salmonella spp. in flocks of laying hens and the factors that influence the occurrence of Salmonella on farms is of the utmost importance. Since 2012, housing laying hens in conventional cages has been prohibited in the European Union, and hens may only be kept in enriched cages or alternative housing systems. The prohibition of conventional cages has improved the welfare of laying hens, but has raised issues concerning the detrimental consequences for the spread and occurrence of infectious diseases in hen flocks. The aim of this study was to analyse the occurrence of Salmonella spp. in laying hen flocks in eastern Croatia in the period from 2020 to 2023, and to determine whether housing systems have an impact on occurrence. During this period, a total of 1534 samples of laying hen faeces from 191 flocks (106 flocks housed in enriched cages and 85 flocks in housing systems with closed outdoor runs) were tested at the Diagnostics Laboratory of the Croatian Veterinary Institute, Veterinary Department Vinkovci, as part of implementation of the National Salmonellosis Control Programme and official sampling in the Republic of Croatia for the presence of Salmonella spp. Isolation, identification and serotyping of Salmonella was conducted in accordance with the standard HRN EN ISO 6579-1:2017/A1:2020 method. Salmonella spp. was confirmed in the faeces of seven laying hen flocks (6.60%) housed in enriched cages, and 11 flocks (12.94%) of laying hens in housing systems with outdoor runs. The research results showed that there was no significant difference in the total occurrence of Salmonella between flocks of laying hens housed in housing systems with outdoor runs and those in enriched cages. The highest percentage of positive flocks was found in 2020 in 11.11% of flocks of laying hens housed in enriched cages and 18.18% of flocks of laying hens kept in housing systems with outdoor runs. When observed by county over the four-year study period, the percentage of positive flocks was significantly higher (P<0.05) in Brod-Posavina County in comparison with Osijek-Baranja County and Vukovar-Srijem County. The research results suggest that there is small possibility that transitioning from enriched cage systems to alternative housing systems, with strict biosecurity measure implementation, would increase Salmonella infections in laying hen flocks.

Evidence-Based Recommendations for Effective Enrichment to Improve the Welfare of Caged Hens Used for Research and Teaching Purposes

Currently, there are no guidelines on housing or recommendations for practical environmental enrichments for chickens used for research and teaching purposes. This study was conducted to identify optimal enrichment programs to improve the health and welfare of caged hens used for teaching and research purposes. The 24-week-old Hy-line Brown laying hens (n = 168) were allocated at random to six enrichment programs/treatments with 14 replicate cages of two birds per cage during a 5-week experiment. Hens had physical access to the following treatments: no enrichment provided (control); round, wooden perches provided (perch); scratch pads made of wood and covered with sandpaper provided (scratch pad); hanging CDs provided (hanging CD); all three enrichment forms provided (complex environment); and each enrichment form provided on a 2-week rotation (novelty). While the egg quality was consistent, the complex group had a significantly lower feed intake (p < 0.001) but similar egg mass; thus, they also had a lower feed conversion ratio (p < 0.001). Additionally, hens in the complex treatment group had the leanest average body weight at week 5 (p < 0.01). It should be noted that while some measures of welfare did show significant differences, the biological or practical difference may be negligible, as in the case of the body condition score in this study. The results show that providing three different forms of environmental enrichment had positive effects on the welfare, health condition, and laying performance of laying hens relative to no enrichment or only one enrichment item.

CFD Investigation on Combined Ventilation System for Multilayer-Caged-Laying Hen Houses.

Mechanical ventilation is an important means of environmental control in multitier laying hen cages. The mainstream ventilation mode currently in use, negative-pressure ventilation (NPV), has the drawbacks of a large temperature difference before and after adjustment and uneven air velocity distribution. To solve these problems, this study designed and analyzed a combined positive and negative-pressure ventilation system for laying hen cages. According to the principle of the conservation of mass to increase the inlet flow in the negative-pressure ventilation system on the basis of the addition of the pressure-wind body-built positive-and-negative-pressure-combined ventilation (PNCV) system, further, computational fluid dynamics (CFD) simulation was performed to analyze the distribution of environmental parameters in the chicken cage zone (CZ) with inlet angles of positive-pressure fans set at 45°, 90°, and 30°. Simulation results showed that the PNCV system increased the average air velocity in the CZ from 0.94 m/s to 1.04 m/s, 1.28 m/s, and 0.99 m/s by actively blowing air into the cage. The maximum temperature difference in the CZ with the PNCV system was 2.91 °C, 1.80 °C, and 3.78 °C, which were all lower than 4.46 °C, the maximum temperature difference in the CZ with the NPV system. Moreover, the relative humidity remained below 80% for the PNCV system and between 80% and 85% for the NPV system. Compared with the NPV system, the PNCV system increased the vertical airflow movement, causing significant cooling and dehumidifying effects. Hence, the proposed system provides an effective new ventilation mode for achieving efficient and accurate environmental control in laying hen cages.

Assessment of positive experiences using associative learning in chickens

To determine whether differences in positive experiences can influence associative learning ability, 2 tasks were conducted with 90 laying hens at the peak of the laying period. The selected hens were reared in a larger flock under the same housing conditions without perches, so they had the same rearing experiences and were moved to either enriched cages or to the floor system at 16 wk of age. They belonged to 3 breeds (Slovenian barred hen: Ba; brown hen: Br; silver hen, S), with 30 hens per breed. The predictor signal, the sound of a clicker, with a 3-second delayed reinforcer (commercial layer feed) was used to mark the desired behaviour (pecking for feed). Hens that associated feed with a clicker (85.06%) were taught 2 tasks, the colour discrimination task (CD) and the target following task (TF). In the CD, the hens had to discriminate between yellow, red and blue colors and peck at a yellow magnet only. In the TF, the desired behaviour was to follow a target, a purple ball on a stick, from 1 perch to another and peck it at the end of the perch. The main results of the hens associating the signal with feed were that the Ba hens learned faster than the S hens (P = 0.006) and required fewer clicker sounds than the Br hens in the CD (P = 0.003). Floor hens that completed CD or TF or both took less time to complete the task (CD, P = 0.03, TF, P = 0.06; both tasks, P = 0.02) or with fewer clicker sounds (CD task; P = 0.02) than cage hens. Although these results suggest that Ba hens and floor hens showed better associate learning performance, probably because they perceived their environment as more rewarding and thus potentially more positive, caution is needed in interpretation considering social experiences and that the ability to perch and the ability to move quickly on a perch can be confounded in TF and both tasks can be confounded with foraging ability.

A detection method for dead caged hens based on improved YOLOv7

In large-scale laying hen farms, daily inspection of dead hens is a relevant task to monitor the health of the flock and prevent disease spreading. The current manual inspection method used in caged hen farms is inefficient, costly, and particularly difficult for high-rise cages. To address this issue, a dead caged hen detection method based on improved You Only Look Once version 7 (YOLOv7) was proposed in this study, which was optimized to improve detection performance and speed in complex farming environments, such as cage wire mesh occlusion and crowded hen occlusion. First, the Convolutional Block Attention Module was used to enable the model to learn target features accurately. Second, the Distance Intersection over Union Non-maximum Suppression and repulsion loss were introduced to improve crowded hen occlusion and reduce missed detections. Additionally, to facilitate the deployment of the proposed method on mobile devices, the MobileNetv3 lightweight network was used to replace the backbone of YOLOv7. Furthermore, the lightweight model was trained using the knowledge distillation method to enhance its performance. Finally, a comparison experiment of different object detection networks and an ablation experiment were conducted to evaluate the proposed method. The experimental results reveal that the improved YOLOv7 model proposed in this study performs optimally. Its precision, recall, F1 score, and mAP@0.5 for the dead hens in the test set are 95.7 %, 86.8 %, 0.910, and 86.2 %, respectively. Compared with the original YOLOv7 model, precision, recall, and mAP@0.5 were increased by 6 %, 10 %, and 13.4 %, respectively. The model parameters and Giga Floating-point Operations were decreased by 31.95 % and 60.56 %, respectively, resulting in a detection speed increase of 43 Frames Per Second. Furthermore, with the assistance of an inspection robot, the proposed dead hen detection model was deployed in the actual farming environments. Compared with methods proposed by other researchers, the proposed model is more suitable for complex actual farming environments and achieves higher detection accuracy, which can offer a reference for automated caged hen detection.

Evaluation of heat stress using temperature-humidity index in laying hens in battery cages under Bursa conditions

Evaluation of heat stress using temperature-humidity index in laying hens in battery cages under Bursa conditions

THE EFFECT OF REARING SYSTEM AND ENVIRONMENTAL TEMPERATURE IN CLOSED HOUSES ON THE ‎LAYING PERFORMANCE

THE EFFECT OF REARING SYSTEM AND ENVIRONMENTAL TEMPERATURE IN CLOSED HOUSES ON THE ‎LAYING PERFORMANCE

Organic eggs as an indirect indicator of agricultural environmental pollution – preliminary research

This study aimed to analyse the heavy metal content in eggs and feeding stuffs dedicated to organically reared birds as an indirect indicator of agricultural environment pollution. The material consisted of 180 table eggs, from caged hens and two organic farms (OF) with different locations. Feed samples were also collected. The samples were mineralised and the content of Ca, Na Mg, K, Fe, Zn, Cu (in yolks) and Pb, Cd, As, Cr (in yolks and feed) was determined. The home-produced feed mixtures contained higher doses of heavy metals (HM) compared to their commercial equivalents. Although no high levels of HM contamination were found in the feed compounds, their content in the eggs was significantly higher than in the feed. Also, depending on the region of the study, metal concentration levels can vary significantly. Due to the area-limited nature of poultry production sites, eggs obtained in specific areas can serve as an indirect and non-invasive bioindicator of environmental HM pollution. The analyse of correlations between particular elements allows to assess the impact and extent of pollutant emitters and to model the areas designated for OF to ensure that the produced food is as safe as possible.

The impact of strain and cage type on the welfare of laying hens in different seasons

The aim of this study was to determine the effects of strain and cage type on the welfare of laying hens in commercial flocks over different seasons. A 2 x 2 x 3 factorial design was used to evaluate the effects of strain (white and brown layers) and cage type (conventional and enrichable battery cages) on the welfare of laying hens over three seasons (winter, spring and summer). The Welfare Quality® Assessment Protocol for Poultry was used to assess the welfare of laying hens. The strain and cage type significantly affected the welfare of the laying hens, which varied according to the season. Hens from the brown strain exhibited higher occurrences of FPD, keel bone abnormalities, and feather loss on the head and neck. White strains displayed a greater percentage of hens with abnormalities in the toe, comb, and beak, along with pecking wounds on the comb and extensive feather loss on the back, rump, and belly. A higher prevalence of comb abnormalities was observed in conventional cages. Hens in enrichable cages had higher rates of FPD, toe, comb and beak abnormalities, as well as pecking wounds on the comb and extensive feather loss. As a result, it was concluded that enrichable cages have a more adverse impact on the welfare of laying hens, with welfare losses in enrichable cages being more pronounced in brown hens compared to white hens and with interactions between strain and cage type varying seasonally.

Effect of monochrome light with different wavelengths on biochemical parameters of hens

Artificial light, as one of the environmental factors, plays a significant role in regulating the synthesis and secretion of hormones related to the coordination of parameters of life, growth, immunity, and reproductive functions of hens. The article aims to study the influence of monochrome light with different wavelengths on the biochemical parameters of hens` blood serum. Four groups of "Hy-Line W-36" crossbred hens were formed. Hens of the 1st group were kept using monochrome light with different wavelength lamps with a wavelength of ~ 460 nm, the 2nd group ~ 600 nm, the 3rd group ~ 630 nm, and the 4th group ~ 650 nm. It was found that the use of light with different wavelengths for keeping hens in cages of multilevel batteries affects hen' biochemical parameters, according to the research results. It was established that when using light with a wavelength of ~ 630 and ~ 650 nm, the indicators of clinical biochemistry of hens' blood serum were within the normal physiological values. Whereas, with the use of light with a wavelength of ~ 600 nm, an increase in the level of glucose, creatinine, total protein, total bilirubin, and phosphorus, a decrease in the ratio of calcium to phosphorus, in the activity of alkaline phosphatase, aspartate aminotransferase, and lactate dehydrogenase, were observed in the hens’ blood serum. The use of light with a wavelength of ~ 460 nm was accompanied by a further increase in the level of glucose, creatinine, total protein, urea, total bilirubin, phosphorus, the activity of alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase, and gamma-glutamyltransferase, a decrease in the ratio of calcium and phosphorus.

Investigation of the Plumage Condition of Non-Beak-Trimmed Rhode ISLAND-Type Pedigree Hens in Cages and Alternative Pens

The extent of the feathers covering a bird’s body and the condition of the plumage largely determine the bird’s well-being and aesthetic condition. This investigation aimed to compare changes in the plumage status of laying hens in dissimilar housing systems in the egg-laying period. The experiment was carried out with 1460 non-beak-trimmed laying hens, provided by Bábolna TETRA Ltd., representing a part of the Rhode-type elite lines (Rhode Island Red (RIR) and Rhode Island White (RIW)) used for breeding brown layer hybrids. Hens were kept in the closed experimental laying house of MATE University (Kaposvár Campus), where the RIR and RIW hens were placed into three types of housing systems: EU standard furnished cage (EU) (7560 cm2; 10 hens/cage; 756 cm2/hen); Alternative pen (A) (5.52 m2, floor and litter combination, 53 hens/pen; 1040 cm2/hen); and Conventional cage (C) (3780 cm2; 6 hens/cage; 630 cm2/hen). The feathering status of the hens was examined at five body parts: neck, breast, wings, back and tail at 33, 45 and 61 weeks of age, which was evaluated on a four-grade scale by the same experienced scorer, and the cumulated plumage point (5–20) was calculated for each hen. The RIW genotype had a better plumage condition than RIR at each of the examined times (at the 33rd week: 19.0, 18.3; at the 45th week: 18.4, 17.4; at the 61st week: 17.2, 15.5). The status of the plumage of the RIR hens had deteriorated to a greater extent. As age progressed, the plumage condition of both genotypes significantly deteriorated in all the three housing technologies. The relatively high level of deterioration can be partly explained by the fact that the animals were non-beak-trimmed. At all test times, the total feather score of the birds in the alternative cage housing was significantly better (at the 33rd week: EU: 18.4, A: 19.1, C: 18.5; at the 45th week: EU: 17.6, A: 18.6, C: 17.4; at the 61st week: EU: 15.9, A: 16.9; C: 16.1). The condition of the neck plumage was better in group RIW than in RIR, and the best in the alternative housing at each test time. At the end, the high decomposition results were striking, since at the beginning there were values close to the maximum (3.98; 3.99). It can be concluded that the reason for the dominantly favorable aviary results is that the hens in this type of housing have to come into contact with fewer mechanical factors, their companions do not jump on their backs when changing places, they do not have to stick their heads out of the grid to collect feed, etc. In addition to all this, they also had a littered scratching area and a nest lined with artificial grass, where they could scratch and take a dust bath.

Effects of different cage sizes and nest settings on laying hen nesting behavior and the proportion of dirty eggs in furnished cages

Furnished cages may promote laying hen welfare more than the traditional cage, but the high proportion of dirty eggs in the furnished cage system could directly affect the exterior quality of eggs, reducing the economic advantage of the furnished cage production system. The problem of the high proportion of dirty eggs reveals defects in the design of the cage, and it may also indicate competition among hens, affecting the utilization of nests. The research aimed to examine the effects of cage size, nest location, and degree of enclosure on behavioral adaptation and the proportion of dirty eggs. Nine hundred laying hens (Hy-line Brown) were housed in cages with eight different types of nests, and the experiment began at the 18 weeks of age and ended at week 38. The proportion of dirty eggs and the nesting behavior of hens were recorded. The number of nest visits and the sitting behavior of the hens in the medium furnished cage were significantly higher than in the large furnished cage (visits: P < 0.01; sitting: P < 0.01). The number of nest visits in the higher nests was significantly greater to lower nests (P = 0.01). The number of nest visits in the enclosed type nests was significantly higher than in the open type nests (P = 0.01). The cage size, nest location, and amount of enclosure had no significant effect on the proportion of dirty eggs (P > 0.05). In conclusion, the enclosed nests in a higher location were more attractive for laying hens.

THE PRODUCTIVITY OF EGG-CROSS CHICKENS DEPENDS ON THEM NUMBERS IN CAGES OF 12-TIER BATTERIES

The group size of hens is one of the key stimuli that affects the welfare of the bird. This is especially important for hens, which evolutionarily live in much smaller groups in the natural environment than in the conditions of enterprises producing edible eggs. But the specific parameters of hеns group size for keeping them in cages of multi-tiered batteries of traditional structures, known as "conventional cages" or "battery cages" according to the international classification, are not regulated by either domestic or foreign standards. There are only restrictions on the minimum number of chickens in one cage of batteries of "improved" designs ("modified enriched cages", or "furnished cages"). It should be at least 7 birds. Therefore, the purpose of the work was to study the productivity and efficiency of the production of edible eggs by increasing group size of hеns in cages of 12-tier batteries of traditional structures from 9 to 93 birds at the standard stocking density (area provision). For this, in the conditions of a modern complex for the production of edible eggs, 4 groups of hens were formed, each of which was kept in a separate poultry house-similar in area (2915 m2), equipped with 12-tier "Big Dutchman" cage batteries, the size and area of which cages differed. The group size of hens on 1st group was 9 birds/cage, 2 groups – 17 birds/cage, 3 groups – 52 birds/cage, 4 groups – 93 birds/cage, density of keeping hens of all groups – 22.6-23.1 birds/m2 with regulatory requirements no more than 25 birds/m2. It was established that an increase the group size of hens in cages from 9 to 93 birds contributes to an increase in the level of preservation (by 5.7%), laying per initial laying hen (by 9.1%), the volume of egg production (by 71.4%), in including based on the calculation per 1 m2 of the poultry house area, the level of profitability of their production from 34.7% to 40.1% and the reduction of the cost price from 1.70 to 1.56 UAH/egg.

Comparative effect of stocking density and flock size on performance and egg quality of laying hens in conventional and furnished California cages

Two experiments were carried out with an objective to test the comparative performance of laying hens reared in conventional California cages vs furnished California cages with regards to production performance, egg quality parameters and immune status. Experiments were conducted at Poultry Research and Training Centre, Department of Poultry Science, Nagpur Veterinary College during 2019-21. Commercial White Leghorn (BV300) hens (n =72) in each experiment were assigned into two treatments with six replicates in conventional and furnished California cages, and reared for a 20 week period. The furnished cages (FC) are provided with perches, nesting area and scratch pad to meet the natural behaviour of the birds. There were two different treatments viz. 548 cm2/b×6 birds and 645cm2/b×6 birds to see the effect of different stocking density in cages. The performance of the laying hens reared in furnished cages were recorded and compared with findings of birds reared in conventional California cages (CC). The results showed that body weight, weight gain, hen day egg production percentages, feed : egg ratio, egg weight and proportion of broken eggs and dirty eggs were not significantly affected by cage types. However, Haugh unit and albumen height of the eggs from furnished cages hens were significantly higher than those from the conventional California cage hens. While H/L ratio and corticosterone values were significantly lowest in furnished cage system birds. It can be concluded from study that the layer birds can be reared in stress free condition in furnished cage system.

The effect of different housing systems on the welfare and the parasitological conditions of laying hens

In Serbia, by 2020, conventional cages will no longer be permitted and hens will be housed in furnished cages. The study was conducted during the winter season on four rearing systems of Lohman Brown hens. For welfare assessment were used indicators from the Welfare quality assessment protocol for poultry. All fecal samples for parasites were qualitatively and quantitatively examined. The results showed that each housing system had positive and negative aspects but overall, hens in cage systems had the highest prevalence of poor plumage condition (47 % and 39%). Hens in conventional cages had more skin lesions (27%) than birds in other systems. Keel bone deformation was the most present in the aviary system (56%) while comb pecking wound in a conventional cage (33%) and free-range system (50%). Hens in the non cage had the highest prevalence of foot pad disorders (32% and 40%). In furnished cages, problems occurred in hens are the lowest. Parasitological examination diagnosed four groups of endoparasites: Coccidia, Trichostrongylidae and Heterakis spp, and Capillaria spp, with a total prevalence of 64% (64/100) only in free-range system. Laying hens in cage systems have a higher expression of negative emotions in relation to the aviary and free-range system. Evidence of negative hens’ emotional condition in cage systems and negative physical condition across all housing systems, suggests that the welfare of modern hens in Serbia is impaired.

A Deep Learning Model for Detecting Cage-Free Hens on the Litter Floor.

Simple SummaryReal-time and automatic detection of chickens such as laying hens and broilers is the cornerstone of precision poultry farming. For laying hens, it is more challenging under cage-free conditions comparing to caged systems. In this study, we developed a deep learning model (YOLOv5x-hens) to monitor hens’ behaviors in cage-free facilities. More than 1000 images were used to train the model and an additional 200 images were adopted to test it. The newly developed YOLOv5x-hens was tested with stable performances in detecting birds under different lighting intensities, angles, and ages over 8 weeks. According to further data analysis, the model performed efficiently in real-time detection with an overall accuracy more than 95%, which is the key step for the tracking of individual birds for evaluation of production and welfare. However, there are still some limitations of the current version of the model. Error detections were caused by highly overlapped stock, uneven light intensity, and images occluded by equipment (i.e., drinking lines and feeders). Future research is needed to address those issues for a higher detection rate. The current study provides technical basis for developing a machine vision system for tracking individual birds for evaluation of animals’ behaviors and welfare status in commercial cage-free houses.Real-time and automatic detection of chickens (e.g., laying hens and broilers) is the cornerstone of precision poultry farming based on image recognition. However, such identification becomes more challenging under cage-free conditions comparing to caged hens. In this study, we developed a deep learning model (YOLOv5x-hens) based on YOLOv5, an advanced convolutional neural network (CNN), to monitor hens’ behaviors in cage-free facilities. More than 1000 images were used to train the model and an additional 200 images were adopted to test it. One-way ANOVA and Tukey HSD analyses were conducted using JMP software (JMP Pro 16 for Mac, SAS Institute, Cary, North Caronia) to determine whether there are significant differences between the predicted number of hens and the actual number of hens under various situations (i.e., age, light intensity, and observational angles). The difference was considered significant at p < 0.05. Our results show that the evaluation metrics (Precision, Recall, F1 and mAP@0.5) of the YOLOv5x-hens model were 0.96, 0.96, 0.96 and 0.95, respectively, in detecting hens on the litter floor. The newly developed YOLOv5x-hens was tested with stable performances in detecting birds under different lighting intensities, angles, and ages over 8 weeks (i.e., birds were 8–16 weeks old). For instance, the model was tested with 95% accuracy after the birds were 8 weeks old. However, younger chicks such as one-week old birds were harder to be tracked (e.g., only 25% accuracy) due to interferences of equipment such as feeders, drink lines, and perches. According to further data analysis, the model performed efficiently in real-time detection with an overall accuracy more than 95%, which is the key step for the tracking of individual birds for evaluation of production and welfare. However, there are some limitations of the current version of the model. Error detections came from highly overlapped stock, uneven light intensity, and images occluded by equipment (i.e., drinking line and feeder). Future research is needed to address those issues for a higher detection. The current study established a novel CNN deep learning model in research cage-free facilities for the detection of hens, which provides a technical basis for developing a machine vision system for tracking individual birds for evaluation of the animals’ behaviors and welfare status in commercial cage-free houses.

Effects of Housing System on Anxiety, Chronic Stress, Fear, and Immune Function in Bovan Brown Laying Hens.

Simple SummaryThe objectives of this study were to determine if housing Bovan brown laying hens in conventional cages or enriched floor pens impacted novel physiological and behavioral markers for animal welfare and whether we can use these markers to assess animal welfare. We found that birds that were housed in conventional cages showed increased tonic immobility durations (indication of fearfulness), decreased fecal Immunoglobulin A (indicator of immune function), and increased feather corticosterone concentrations (indicator of chronic stress) compared to hens that were housed in enriched pens. These results indicate that caged birds are more stressed, have reduced immune function, and are more fearful than birds that are housed in pens. In contrast to expectations, we found that caged hens showed a shorter latency to feed during attention bias testing, indicating reduced anxiety compared to birds from pens. Overall, we found that conventional cages generally impacted animal welfare negatively, with the exception of anxiety. In addition, the results suggest that the chosen novel markers for animal welfare show appropriate contrast between long-term housing systems for laying hens. Yet, additional work needs to be done before these measures can be used more broadly.The scientific community needs objective measures to appropriately assess animal welfare. The study objective was to assess the impact of housing system on novel physiological and behavioral measurements of animal welfare for laying hens, including secretory and plasma Immunoglobulin (IgA; immune function), feather corticosterone (chronic stress), and attention bias testing (ABT; anxiety), in addition to the well-validated tonic immobility test (TI; fearfulness). To test this, 184 Bovan brown hens were housed in 28 conventional cages (3 birds/cage) and 4 enriched pens (25 birds/pen). Feces, blood, and feathers were collected 4 times between week 22 and 43 to quantify secretory and plasma IgA and feather corticosterone concentrations. TI tests and ABT were performed once. Hens that were from cages tended to show longer TI, had increased feather corticosterone, and decreased secretory IgA at 22 weeks of age. The caged hens fed quicker, and more hens fed during the ABT compared to the penned hens. Hens that were in conventional cages showed somewhat poorer welfare outcomes than the hens in enriched pens, as indicated by increased chronic stress, decreased immune function at 22 weeks of age but no other ages, somewhat increased fear, but reduced anxiety. Overall, these novel markers show some appropriate contrast between housing treatments and may be useful in an animal welfare assessment context for laying hens. More research is needed to confirm these findings.

EVALUATIONS OF MECHANICAL PROPERTIES FOR FREE-RANGE AND CAGED CHICKEN FEMURS

ABSTRACT This study focuses on investigating the femoral bone properties of both caged and free-range chickens using the mechanical test techniques. Intact femurs extracted from both caged and free-range chickens were subjected experimentally to three-point bending and tensile tests to obtain the material properties. Each test has performed particular applications considering the relevant standards. Two different modular fixtures were developed and used to calculate the mechanical properties of the chicken femurs. This study aims to investigate the usability of the chicken femurs for biomechanical studies to imitate human bones in terms of strength and define the property differences between the caged and free-range hens’ femurs. The results were presented and some significant femur differences were observed between the two groups of hens’ femurs. The modulus of elasticity (E) and ultimate strength (σUTS ) values of the free-range hens’ femurs were found to be about 51% and 15% higher than the caged hen’s femurs. The findings of the present study were found to be compatible with those of the studies in the literature. The results suggested that the chicken intact femurs can be used in biomechanical studies for orthopaedic applications instead of the real human bone material model with similar properties.

Not So Happy Hens

An international company has been promoting itself as producing happy eggs. The commercials offer pictures of hens living in idyllic conditions—free to roam in wide grass lands replete with sunshine and trees in which to shelter. Intrigued by these commercials, one of us wrote to the company concerned and inquired whether the millions of male chicks were similarly cared for. The response was that male chicks (surplus to requirements) were killed “using a pain free gas when they are 1 day old” (personal communication, 2016). When we inquired what happened to hens at the end of their apparent breeding life, we were informed that “when our girls no longer produce eggs we can sell to the supermarkets they are taken to our facility where they are exposed to a nonaversive gas to put them to sleep” (personal communication, 2016).Leaving aside whether it is morally licit to raise hens for their eggs, it is clear then that the current system of commercial egg production (at least in this case) is predicated on the slaughter of millions of hens and their male counterparts.This should give every ethical consumer pause for thought.Some animal-friendly agencies now ask animal advocates to keep and care for caged hens when farmers judge they are surplus to requirements at the end of their breeding life (British Hen Welfare Trust, 2021; Fresh Start for Hens, n.d.). Many animal advocates out of compassion have now taken up this opportunity to give hens a new life and, as a result, sometimes eat the eggs they may produce (hens do not require a male to make eggs). Looking after ex-battery hens in these circumstances does not invite moral censure.But it should be clear that commercial egg production, such as described above, is vexing because it is not only the welfare of hens that is morally important, but also their individual lives. Suffering (and apparent well-being) is not the only legitimate moral concern. Animals matter as individuals, and causing death needs serious moral justification.At the very least, businesses that exploit hens should make clear through advertisements and labeling not only the conditions in which their hens are kept, but also the manner and number of deaths that the system itself requires.