Behaviour Of Hens Research Articles

Nest box-mounted PIT tag readers reveal cryptic recruits of cavity-nesting waterfowl in south Louisiana

Black-bellied Whistling-Ducks (Dendrocygna autumnalis; BBWD) are rapidly expanding northward into the core range of the eastern Wood Duck (Aix sponsa; WODU), yet little is known about BBWD nesting ecology. Typical field methods to study cavity-nesting waterfowl (i.e., weekly nest monitoring) preclude a full understanding of important breeding information, including nest prospecting and parasitic egg laying. To address this, we used subcutaneous passive integrated transponder (PIT) tags embedded in adults and PIT tag readers mounted on nest boxes with the objective to (1) identify individuals that used nest boxes but were not physically captured on a nest, (2) quantify box visitation, and (3) quantify BBWD pair and WODU hen behaviors during the prospecting, laying, and incubation periods. We deployed RFID readers on 40 nest boxes from March–December 2022 in Louisiana with the potential to detect BBWD and WODU marked with PIT tags in 2020–2022. We detected 48 (BBWD n = 26, WODU n = 22) adults of both species via RFID readers, and 33% (n = 16) of individuals (50% of BBWD, n = 12; 14% of WODU, n = 3) were never otherwise recaptured in 2022, meaning that traditional field methods for cavity-nesting waterfowl fail to document a substantial number of birds potentially contributing to the population via parasitism. We also used Bayesian generalized linear models to determine that both species visited a similar number of “new” (< 1 year old) and “old” (> 1 year old) nest boxes (β = 0.66, CI = -0.30, 1.64). However, BBWD preferentially visited (and subsequently nested in) old boxes at a significantly higher rate than WODU (β = 1.32, CI = 0.97, 1.66). Due to the generalist nature and rapid expansion of BBWD, an apparent aversion to newly installed boxes was unexpected, especially since there were several successful WODU nests in the new boxes before BBWD began nesting in 2022. Our study is one of the first to evaluate BBWD nesting behaviors within the core WODU breeding range, and the first to use nest box-mounted PIT tag readers to observe BBWD behavior.

Radiographic, computed tomographic, and histologic characteristics of bone for clinically normal laying hens in a free-range housing system.

Laying hens are increasingly being kept in backyard flocks and considered family pets; however, diagnostic imaging characteristics of bone for clinically normal backyard hens are currently limited. This prospective, descriptive study was to describe radiographic, computed tomographic, and histologic characteristics of bone for a group of clinically normal laying hens housed in conditions comparable to those of backyard flocks. Sixteen 60-week-old Lohmann Brown laying hens were included. Hens were housed in a free-range unit with outdoor access at a university research and teaching farm. Hens were defined as clinically normal by the farm manager and a veterinary researcher in laying hen behavior and welfare. Findings from the horizontal beam, left lateral, sternal radiographs (n=16), postmortem, and whole-body CT scans (n=4) were recorded by a veterinary radiologist and a research technician. Histologic findings for sternal, femoral, and tibiotarsal bone samples (n=5) were recorded by a veterinary pathologist. The most frequent radiographic findings for the sternal carina (keel bone) were smoothly marginated concave deviations of the ventral margin and caudal section fractures. Multiple punctate mineral opacities (PMOs) were present in radiographs and CT images for all hens and were involved in the sternal carina and multiple other bones in the axial and appendicular skeleton. No bone abnormalities were identified in any histologic sections where PMOs were radiographically detected. Authors propose that PMOs are normal radiographic and CT findings in the bones of mature, laying hens and may represent temporary calcium reservoirs formed during osteoclastic activities.

Spatiotemporal understanding of behaviors of laying hens using wearable inertial sensors

Automatic detection of behaviors and locations has been increasingly needed in the management of non-cage systems where hen behaviors are highly diverse and active. Here we show a technology to spatiotemporally understand behaviors using a wearable inertial sensor, containing a three-axis accelerometer and three-axis angular velocity sensor (i.e., gyroscope), and a marker. Using supervised machine learning, we first developed a tool that automatically classified and counted 11 behaviors, including comfort behaviors such as head scratching and tail-wagging with small movements as well as dust-bathing with dynamic movements. As expected, these behaviors were observed more frequently in floor pens than in conventional cages (all P < 0.01). We also spatially mapped the behaviors in floor pens and visualized the behavioral frequency in each resource by detecting the colored markers on the sensor. Furthermore, using the time-series information included in the sensor data, we analyzed the behavioral transition from one behavior to another. The behavioral transitions were more complex in floor pens, and the number was higher in body shaking, tail-wagging, resting, litter scratching, dust-bathing, preening, and moving in floor pens than in conventional cages (all P < 0.05). Our tools presented deeper insights into where and what hens behaved and also suggested that connectivity between behaviors, as well as observing the frequency of a behavior, can be an important indicator for welfare assessment in laying hens.

Monitoring activity index and behaviors of cage-free hens with advanced deep learning technologies

Chickens’ behaviors and activities are important information for managing animal health and welfare in commercial poultry houses. In this study, convolutional neural networks (CNNs) models were developed to monitor the chicken activity index. A dataset consisting of 1,500 top-view images was utilized to construct tracking models, with 900 images allocated for training, 300 for validation, and 300 for testing. Six different CNN models were developed, based on YOLOv5, YOLOv8, ByteTrack, DeepSORT, and StrongSORT. The final results demonstrated that the combination of YOLOv8 and DeepSORT exhibited the highest performance, achieving a Multi-Object Tracking Accuracy (MOTA) of 94%. Further application of the optimal model could facilitate the detection of abnormal behaviors such as smothering and piling, and enabled the quantification of flock activity into three levels (low, medium, and high) to evaluate footpad health states in the flock. This research underscores the application of deep learning in monitoring poultry activity index for assessing animal health and welfare.

Research note: A method for recognizing and evaluating typical behaviors of laying hens in a thermal environment

Automatically identifying abnormal behaviors of caged laying hens in a thermal environment improves manual management efficiency. It also provides reference indicators for breeding heat-tolerant hens. In this study, we propose a deep learning-based method for automatic recognition and evaluation of typical heat stress behaviors in hens. We developed a lightweight object detection algorithm, YOLO-HGP, based on the YOLOv8n as the baseline model. YOLO-HGP achieves Precision (P), Recall (R), and mean average precision (mAP) of 95.952%, 94.127%, and 97.667%, respectively, effectively detecting typical heat stress behaviors in hens. Compared to the original YOLO v8n, YOLO-HGP improves R, and mAP by 6.257%, and 1.963%, respectively. The FLOPs (floating point operations) and parameter count of YOLO-HGP are 4.3G and 1.729M, reducing by 47.56% and 42.58% compared to the original model. Additionally, we introduce the "ORC-ratio" (The ratio of the combined frequency of open-beak breathing and retching behaviors to the frequency of closed-beak behaviors.) as an evaluation indicator for the frequency of typical heat stress behaviors in hens and combine it with the Hybrid-SORT multiobject tracking algorithm to achieve tracking detection of individual hens. The study demonstrates that the proposed model effectively identifies and quantitatively evaluates typical behaviors of hens in a thermal environment, providing an effective approach for the automated recognition of heat stress behaviors in hens.

Enhancing Dust Control for Cage-Free Hens with Electrostatic Particle Charging Systems at Varying Installation Heights and Operation Durations

The poultry industry is shifting towards more sustainable and ethical practices, including adopting cage-free (CF) housing to enhance hen behavior and welfare. However, ensuring optimal indoor air quality, particularly concerning particulate matter (PM), remains challenging in CF environments. This study explores the effectiveness of electrostatic particle ionization (EPI) technology in mitigating PM in CF hen houses while considering the height at which the technology is placed and the duration of the electric supply. The primary objectives are to analyze the impact of EPI in reducing PM and investigate its power consumption correlation with electric supply duration. The study was conducted in a laying hen facility with four identical rooms housing 720 laying hens. The study utilized a Latin Square Design method in two experiments to assess the impact of EPI height and electric supply durations on PM levels and electricity consumption. Experiment 1 tested four EPI heights: H1 (1.5 m or 5 ft), H2 (1.8 m or 6 ft), H3 (2.1 m or 7 ft), and H4 (2.4 m or 8 ft). Experiment 2 examined four electric supply durations: D1 (control), D2 (8 h), D3 (16 h), and D4 (24 h), through 32 feet corona pipes. Particulate matter levels were measured at three different locations within the rooms for a month, and statistical analysis was conducted using ANOVA with a significance level of ≤0.05. The study found no significant differences in PM concentrations among different EPI heights (p &gt; 0.05). However, the duration of EPI system operation had significant effects on PM1, PM2.5, and PM4 concentrations (p &lt; 0.05). Longer EPI durations resulted in more substantial reductions: D2—17.8% for PM1, 11.0% for PM2.5, 23.1% for PM4, 23.7% for PM10, and 22.7% for TSP; D3—37.6% for PM1, 30.4% for PM2.5, 39.7% for PM4, 40.2% for PM10, and 41.1% for TSP; D4—36.6% for PM1, 24.9% for PM2.5, 38.6% for PM4, 36.3% for PM10, and 37.9% for TSP compared to the D1. These findings highlight the importance of prolonged EPI system operation for enhancing PM reduction in CF hen houses. However, utilizing 16 h EPI systems during daylight may offer a more energy-efficient approach while maintaining effective PM reduction. Further research is needed to optimize PM reduction strategies, considering factors like animal activities, to improve air quality and environmental protection in CF hen houses.

Genetic Foundation of Male Spur Length and Its Correlation with Female Egg Production in Chickens.

Spurs, which mainly appear in roosters, are protrusions near the tarsometatarsus on both sides of the calves of chickens, and are connected to the tarsometatarsus by a bony core. As a male-biased morphological characteristic, the diameter and length of spurs vary significantly between different individuals, mainly related to genetics and age. As a specific behavior of hens, egg-laying also varies greatly between individuals in terms of traits such as age at first egg (AFE), egg weight (EW), and so on. At present, there are few studies on chicken spurs. In this study, we investigated the inheritance pattern of the spur trait in roosters with different phenotypes and the correlations between spur length, body weight at 18 weeks of age (BW18), shank length at 18 weeks of age (SL18), and the egg-laying trait in hens (both hens and roosters were from the same population and were grouped according to their family). These traits related to egg production included AFE, body weight at first egg (BWA), and first egg weight (FEW). We estimated genetic parameters based on pedigree and phenotype data, and used variance analysis to calculate broad-sense heritability for correcting the parameter estimation results. The results showed that the heritability of male left and right spurs ranged from 0.6 to 0.7. There were significant positive correlations between left and right spur length, BW18, SL18, and BWA, as well as between left and right spur length and AFE. We selected 35 males with the longest spurs and 35 males with the shortest spurs in the population, and pooled them into two sets to obtain the pooled genome sequencing data. After genome-wide association and genome divergency analysis by FST, allele frequency differences (AFDs), and XPEHH methods, we identified 7 overlapping genes (CENPE, FAT1, FAM149A, MANBA, NFKB1, SORBS2, UBE2D3) and 14 peak genes (SAMD12, TSPAN5, ENSGALG00000050071, ENSGALG00000053133, ENSGALG00000050348, CNTN5, TRPC6, ENSGALG00000047655,TMSB4X, LIX1, CKB, NEBL, PRTFDC1, MLLT10) related to left and right spur length through genome-wide selection signature analysis and a genome-wide association approach. Our results identified candidate genes associated with chicken spurs, which helps to understand the genetic mechanism of this trait and carry out subsequent research around it.

Male chicks play more than females – sex differences in chicken play ontogeny

Play indicates positive affective states and can therefore potentially be used as an indicator of positive welfare. Sex differences in play has been reported in many mammalian species, but in birds, this is still to be explored. It is known that young chickens perform play behavior during their early ontogeny, but potential sex differences have not previously been addressed. Therefore, we aimed to investigate potential sex effects on play ontogeny in young chickens, by comparing play occurrence in young males and females of a commercial hybrid of White Leghorn. Eighteen chicks of each sex were hatched in the same incubator and then housed in sex-separated groups. Six groups of three chicks each were randomly created for each sex, and the same three chicks were then moved to enriched play arenas twice per week, from day 6 until day 53 post hatch. The frequency of different play behaviors, categorized as locomotor play, social play and object play were recorded during 30 min on each observation day. Each group of three birds constituted the independent statistical replicate. Males played significantly more than females, due to more social and object play, whereas for locomotor play, no difference was found between the sexes. In conclusion, clear sex differences in play in chickens was demonstrated, and this may be linked to the highly sexually dimorphic behavior of adult cockerels and hens. Further research is needed to elucidate the relationships between type and frequency of play in chicks and later behavior as adults.

Research Note: Differences in the pecking behavior of turkey hens in proximity to the feeding pan depending on their beak condition

The present study aimed to provide further insight on different pecking behavior of beak-trimmed and untrimmed turkey hens in proximity to the feeding pan. Investigations were carried out in 4 housing compartments with female fattening turkeys where video were recorded and evaluated with regard to 4 different types of (pecking-) behavior (feeding, pecking on the ground, pecking at conspecifics, being pecked) observed in 1 focal animal in proximity to each feeding pan. Concerning the median duration, there were only small differences between the animals with different beak conditions. Pecking behavior varied in how many animals exhibited 'pecking on the ground' with more turkeys with intact beaks showing this activity in proximity to the feeding pan with a slightly increased median duration (0:06 vs. 0:04 min). Further discrepancies were observed in the maximum duration of recorded behaviors, as there were animals with intact beaks that showed "pecking on the ground" (4:09 vs. 2:54 min), "pecking at conspecifics" (3:46 vs. 1:25 min), and were "being pecked" (0:52 vs. 0:35 min) for a longer period of time. Based on this result, however, it can be assumed that especially individual animals with an intact beak forage more intensively and perform some pecking behaviors, which include injurious pecking, with longer duration in proximity to the feeding pan.

How does visible light flicker impact laying hen pullet behavior, fear, and stress levels?

Many characteristics of artificial light have been evaluated; however, light-flicker frequency (F) has not been assessed extensively in poultry. Pullets (1,344 per strain [S]; Lohmann Brown-Lite [LB] and LSL-Lite [LW]) were placed into 8 light-tight rooms, containing 6 floor pens (15 pen replicates per F × S for 30 and 250 Hz; 18 pen replicates per F x S for 90 Hz), and assigned 1 of 3 F treatments (30, 90, 250 Hz). The experiment took place over 2 trials (blocks). To evaluate long-term effects of F during rearing, birds were followed through the hen phase. Data were analyzed using Proc Mixed (SAS 9.4). Differences were considered significant when P ≤ 0.05, and behaviors are expressed as percentage of time. Pullets reared under 30 Hz spent more time performing nutritive behaviors (P < 0.01) and as "unidentified" (P = 0.02) than other treatments. Active behavior demonstrated an age x F interaction, with pullets being more active at 16 wk, regardless of F (P < 0.01). Comfort behaviors were higher at 16 wk compared to other ages, regardless of F (P < 0.01). Exploratory behaviors were lowest at 4 wk in pullets under 30 Hz (P < 0.01). Aggressive behaviors (12 wk) were higher in pullets reared under 250 Hz than those under 90 Hz (P < 0.01). Comb score was unaffected by F (P = 0.79) and all birds scored had a full plumage. Heterophil-to-lymphocyte ratio was unaffected by F at 7 or 15 wk (P = 0.85 and P = 0.54, respectively). In trial 1, pullets reared under 90 Hz had higher corticosterone concentrations than those reared under 250 Hz (P = 0.02) and trial 2 there were no effects of F (P = 0.97). For novel object test, LW pullets reared under 90 Hz had a higher latency to peck than LW pullets under 30 Hz or 250 Hz (P = 0.03). Hen behavior (wk 39) and fear tests (36 wk; novel object test (P = 0.86) and tonic immobility (P = 0.37)) were unaffected by F. Overall, minimal effects of F were seen on pullet and hen behavior and stress.

Do flickering lights impact turkey hen behavior, stress, and fear?

Little is known about the effect of light-flicker frequency on poultry, particularly on turkeys. This experiment examined the impact of light-flicker frequency on the behavior, stress, and fear response of Nicholas Select turkey hens reared to 11 wk. The experiment was a randomized complete block design (2 trials), with a one-way factorial analysis evaluating 3 light-flicker frequencies (30, 90, or 195 Hertz; Hz). Birds (n = 3,276 per trial) were housed in 9 individual environmentally controlled rooms (3 replicates per treatment per trial). Data collected included: behavior (4, 8, and 10 wk), incidence of aggressive damage, heterophil-to-lymphocyte ratio, and novel object test (daily d 1-7 and at 4, 8, and 11 wk). Data were analyzed using Proc Mixed (SAS 9.4), with significance declared at P ≤ 0.05. Behavior data are presented as the percentage of time spent performing the behavior. At 4 wk, gentle feather pecking and exploratory behaviors were higher under 195 Hz compared to 30 Hz (P = 0.04 and P = 0.05, respectively). Preening was higher under 90 Hz compared to 30 Hz (P = 0.05). At 8 wk, wing flapping was lowest under 195 Hz (P < 0.01). Gentle feather pecking was higher under 90 and 195 Hz compared to 30 Hz (P = 0.02). Fighting (P = 0.05), aggressive pecking (P = 0.02), and aggressive behaviors (P = 0.01) were lower under 30 Hz compared to 90 Hz. At 10 wk, preening was decreased under 30 Hz (P = 0.03). Incidences of aggressive damage were reduced under 30 Hz compared to 90 Hz (0 d-4 wk; P = 0.01) and under 30 compared to both 90 and 195 Hz (4-8 wk; P = 0.01). At 11 wk, heterophil-to-lymphocyte ratios were lowest under 30 Hz (P = 0.04). The novel object test was unaffected by flicker treatment. In conclusion, many behaviors and the stress and fear responses were unaffected by either visible or non-visible flicker. However, visible flicker (30 Hz) reduced some comfort and exploratory behaviors early in life, and the impact on preening continued to older ages, suggesting minor negative impacts of flicker, particularly early in life.

Effects of ultraviolet light supplementation on hen behaviour and welfare during early lay

Poultry can see in the ultraviolet (UV) spectrum and supplementation of UVA has been shown to reduce laying hens’ fear and stress. The shorter wavelengths (UVB) also facilitate vitamin D3 production. However, UV spectrums are typically not included in indoor commercial poultry lighting which may result in less than optimum welfare of laying hens. This study predicted that UVA and UVA/B supplementation would increase desirable behaviours such as foraging and exploratory pecking and reduce measures of fear and stress. The effects of UV light supplementation were assessed on 252 ISA Brown hens during the period from 16 to 27 weeks of age. Birds were housed in eighteen pens (14 hens/pen) under three different light treatment groups each with six replications: (i) UV0: standard control lighting with LED white light, (ii) UVA: control lighting plus a supplemental ‘daylight’ avian bulb providing UVA, and (iii) UVA/B: control lighting plus a supplemental full spectrum reptile bulb containing both UVA and UVB wavelengths. Behavioural time budgets were assessed in the home pens at 18 and 24 weeks. At 20, 23, and 26 weeks, assessments included: individual behavioural tests of tonic immobility and open field, pen-level novel object tests and blood heterophil/lymphocyte (H/L) ratios. At 27 weeks the UV supplemental lights were turned off for 3 days as a ‘stressor’ with bird locations in the pen measured before and during the stressor, along with H/L ratio and attention bias test assessments. Results showed limited effects of the supplemental lights. At 26 weeks both UV light treatments reduced tonic immobility duration (P = 0.006) and vocalisations across time in the open field test (P = 0.0003), while the UVA/B hens had lower H/L ratios than the UV0 hens (P = 0.01). However, removing the treatment lights did not result in greater stress and anxiety and there were few differences observed in the home pen time budgets. Overall, these results align with complementary findings in the same birds showing minimal impact of the UV treatments on measures of egg production, egg quality, bone health, and circulating plasma P and Ca but with an increase in serum vitamin D (25(OH)D3) for the UVA/B hens. The supplemental UV lights in this study were only on one side of the pens which could have minimised their impacts. Similarly, effects may vary at different points in the production cycle than included in this study.

Observation on breeding behavior of white breasted water hen (Amaurornis phoenicurus: Pennant, 1769) in the wetlands of East Calcutta, and Behala

Observation on breeding behavior of white breasted water hen (Amaurornis phoenicurus: Pennant, 1769) in the wetlands of East Calcutta, and Behala

Effects of cage type and the light-dark cycle on the behavior of hens subjected to forced molting.

In this study, the effects of cage type and the light-dark cycle on the behavior of hens before, during, and after forced molting were determined. For this purpose, 73-week-old hens were placed in the two different cage types used in the experiment. The barley method was used to induce molting at 75 weeks of age. The molting period lasted 35 days in total. The frequencies of walking, feeding, comforting, and preening behaviors were affected by the forced molting period. The addition of enrichment materials to the cage did not cause any changes in hen behavior. The light-dark cycle was important for the frequency of all examined behaviors except fighting behavior. No interaction was found among forced molting period, cage type, and light-dark cycle regarding behaviors. It is thought that there is a decrease in welfare-related behaviors at the end of the laying period and this decrease does not increase with forced molting using barley; on the contrary, appropriate forced molting applied to hens during this period will increase welfare. It was observed that cage type did not cause a significant difference in hen behavior during the forced molting period.

Domestic chicken hens can eavesdrop on the alarm calls of wild tits

Eavesdropping on heterospecific alarm calls is common in nature, and successful eavesdropping on heterospecific call information can provide benefits to animal survival. Previous studies have shown that free-ranging flocks of domestic chickens can respond to avian heterospecific alarm calls. However, there are limited studies on whether solitary active domestic chickens (Gallus gallus domesticus), especially hens with chicks eavesdrop on heterospecific alarm calls to detect different types of predators and adjust their response depending on whether the predators are a threat to themselves or their young. In the present study, we evaluated the behavioral responses of hens with chick activity to two alarm calls (test playback) and territorial calls (control playback) of wild Japanese tits (Parus minor). The results showed that hens were more vigilant toward the alarm calls than territorial calls and that anti-predator behavior differed significantly between the two alarm calls as predicted: they engage in self-preservation behaviors when the call informs about aerial predators, and in protective behaviors of their chicks when the calls inform about ground predators. In the later case, the number of chicks also has an impact on the behavior of hens (dilution effect). This suggests that hens can eavesdrop on the alarm call of Japanese tits, identify predator information in the alarm call, and adjust the anti-predation strategy based on the type of alarm and the number of chicks.

Influence of keel impacts and laying hen behavior on keel bone damage

Keel bone damage, which presents as fractures and/or deviations of the keel, has been detected in laying hens housed in all types of systems. Factors leading to keel bone damage in hens housed with limited vertical space, such as those housed in furnished systems, are not well understood, and are the topic of this study. Ten focal hens from each of 12 furnished cages (4 rooms of 3 cages) were fitted with keel mounted tri-axial accelerometers. Their behavior was video recorded continuously over two 3-wk trials: the first when the hens were between 52 and 60 wk of age, and the second approximately 20 wk later. The integrity of each hen's keel was evaluated at the start and end of each 3-wk trial using digital computed tomography. We identified predominant behaviors associated with acceleration events sustained at the keel (collisions, aggressive interactions and grooming) by pairing accelerometer outputs with video data. For each recorded acceleration event we calculated the acceleration magnitudes as the maximum summed acceleration recorded during the event, and by calculating the area under the acceleration curve. A principle components analysis, which was used as a data reduction technique, resulted in the identification of 4 components that were used in a subsequent regression analysis. A key finding is that the number of collisions a hen has with structures in her environment, and the number of aggressive interactions that a hen is involved, each affect the likelihood that she will develop 1 or more fractures within a 3-wk time span. This relationship between hen behavior and keel fracture formation was independent of the magnitude of acceleration involved in the event. Observed behavior did not have an impact on the formation of keel bone deviations, further supporting reports that the mechanisms underlying the 2 types of keel bone damage are different.

The necessity of pen replication to account for and understand the impacts of social dynamics on individual laying hen behavior

Individual laying hens within the same group show variation in their temperament traits and cognitive learning abilities, which can be affected by both their early rearing experiences and housing environments. Hens also have distinct individual patterns of movement within housing systems that may correlate with temperament and cognition. Individual behavioral tests can measure treatment impacts, but social dynamics may impact on an individual’s behavior. The aims of this perspective piece are to provide further evidence of pen-level variation using original data on social ranging patterns and fear assessment of free-range hens exposed to different, enriched rearing environments; and to encourage more studies to consider pen replicate variation as a means to better understand causes and mechanisms. A literature review showed that, while most published studies over the past decade assessing individual laying hen behavior included group-level replication (i.e., 83% of 54 articles reviewed), almost none considered inter-pen variation. The original data analysis of individual hens’ range use recordings showed significant treatment pen replicate variation in pop-hole following movements and hen–pair associations in the time spent together inside or outside. Significant inter-pen variation was also seen in tonic immobility tests on a subset of hens from the same study. Pen-level replication is important for scientific validity and for improving our understanding of why commercial flocks in the same environment can be so variable in their behavior to inform management practices. Further research could help to understand the mechanisms behind why groups of hens reared and housed in the same environments will show significant inter-group variation.

Backpack satellite transmitters reduce survival but not nesting propensity or success of greater sage-grouse.

Telemetry technology is ubiquitous for studying the behavior and demography of wildlife, including the use of traditional very high frequency (VHF) radio telemetry and more recent methods that record animal locations using global positioning systems (GPS). Satellite-based GPS telemetry allows researchers to collect high spatial-temporal resolution data remotely but may also come with additional costs. For example, recent studies from the southern Great Basin suggested GPS transmitters attached via backpacks may reduce the survival of greater sage-grouse (Centrocercus urophasianus) relative to VHF transmitters attached via collars that have been in use for decades. While some evidence suggests GPS backpacks reduce survival, no studies have examined the effects of GPS backpacks on breeding behavior and success. Therefore, we compared survival, breeding behavior, and nest success of sage-grouse hens marked with both VHF collars and GPS backpack transmitter over a 7-year period in central Idaho, USA. GPS backpacks reduced spring-summer survival of sage-grouse hens relative to hens with VHF collars, where daily mortality probability was 68%-82% higher from March 1 to August 1. Yet satellite GPS backpacks did not consistently affect nest success or the likelihood or timing of nest initiation relative to VHF collars. Daily nest survival varied annually and with timing of nest initiation and nest age, but marginal effects of transmitter type were statistically insignificant and interactions between transmitter type and study year produced no meaningful patterns. Our results corroborate recent studies for the effect of satellite GPS backpacks on sage-grouse survival, but also suggest that these transmitters do not appear to affect components of fecundity. Our results therefore add important context to recent debate surrounding the effects of GPS backpacks on sage-grouse, and the relative strengths and weaknesses of different transmitter types for understanding behavior and population dynamics.

Assessment of Preference Behavior of Layer Hens under Different Light Colors and Temperature Environments in Long-Time Footage Using a Computer Vision System.

As for all birds, the behavior of chickens is largely determined by environmental conditions. In many production systems, light intensity is low and red feather strains have low contrast with the background, making it impossible to use conventional image segmentation techniques. On the other hand, studies of chicken behavior, even when using video camera resources, depend on human vision to extract the information of interest; and in this case, reduced samples are observed, due to the high cost of time and energy. Our work combined the use of advanced object detection techniques using YOLO v4 architecture to locate chickens in low-quality videos, and we automatically extracted information on the location of birds in more than 648 h of footage. We develop an automated system that allows the chickens to transition among three environments with different illuminations equipped with video cameras to monitor the presence of birds in each compartment, and we automatically count the number of birds in each compartment and determine their preference. Our chicken detection algorithm shows a mean average precision of 99.9%, and a manual inspection of the results showed an accuracy of 98.8%. Behavioral analysis results based on bird unrest index and permanence time indicate that chickens tend to prefer white light and disfavor green light, except in the presence of heat stress when no clear preference can be observed. This study demonstrates the potential of using computer vision techniques with low-resolution, low-cost cameras to monitor chickens in low-light conditions.

Evaluating Behavior Recognition Pipeline of Laying Hens Using Wearable Inertial Sensors.

Recently, animal welfare has gained worldwide attention. The concept of animal welfare encompasses the physical and mental well-being of animals. Rearing layers in battery cages (conventional cages) may violate their instinctive behaviors and health, resulting in increased animal welfare concerns. Therefore, welfare-oriented rearing systems have been explored to improve their welfare while maintaining productivity. In this study, we explore a behavior recognition system using a wearable inertial sensor to improve the rearing system based on continuous monitoring and quantifying behaviors. Supervised machine learning recognizes a variety of 12 hen behaviors where various parameters in the processing pipeline are considered, including the classifier, sampling frequency, window length, data imbalance handling, and sensor modality. A reference configuration utilizes a multi-layer perceptron as a classifier; feature vectors are calculated from the accelerometer and angular velocity sensor in a 1.28 s window sampled at 100 Hz; the training data are unbalanced. In addition, the accompanying results would allow for a more intensive design of similar systems, estimation of the impact of specific constraints on parameters, and recognition of specific behaviors.