Individual Monitoring of Activity and Lameness in Conventional and Slower-Growing Breeds of Broiler Chickens Using Accelerometers

Accelerometers are increasingly being investigated to detect animal behavior as a method for monitoring individual welfare that overcomes manual challenges associated with time, resource, and discrete sampling. We investigated the effects of broiler chicken hybrid (hereafter breed) and weight on accelerometer activity (activityA; calculated as percentage of time spent active (%)) and its association with lameness as a major broiler welfare concern. Accelerometers were attached to birds of different breeds on between 2 and 4 occasions from 26 to 30 days old (conventional breed CNV) and 26 to 49 days old (two slower-growing breeds SGH; SGN). At 2.2 kg, lameness was scored using a 6-point gait scoring system (0: unaffected to 5: severely lame). Linear mixed effects models and breed-stratified generalized linear models together with a random-effect meta-analysis were used for data analyses. ActivityA was lower in faster-growing, heavier birds compared to slower-growing, lighter birds, showing overall consistency with previous behavioral research, but did not vary linearly with gait score. Accelerometers offer the potential for simple broad-scale continuous monitoring of broiler chicken activity behavior that requires limited data processing. Exploration of the ability of accelerometers to capture more subtle and specific changes in behavioral patterning, such as non-linear acceleration with gait score that could indicate early development of lameness, warrants further investigation.

Impact of Body-worn Sensors on Broiler Chicken Behavior and Agonistic Interactions

Technology, like body-worn sensors, enables data collection from similar-looking individuals in large groups but may alter behavior. We aimed to evaluate the impact of body-worn sensors on broiler behavior. Broilers were housed in 8 pens (10 birds/m2). At 21 days-old, 10 birds/pen were fitted with a harness contained a sensor (HAR), while the remaining 10-birds were unharnessed (NON). Behaviors were recorded on days 22-26 using scan sampling (126 scans/day for 5 days). Percent of birds performing behaviors were calculated daily for each group (HAR-or-NON), and agonistic interactions were identified based on birds involved (two NON-birds (N-N), NON-aggressor to HAR-recipient (N-H), HAR-aggressor to NON-recipient (H-N), or two HAR-birds (H-H)). HAR-birds performed locomotory behavior and explored less often than NON-birds (p<0.05). Consummatory behavior was unaffected by treatment on any day (p>0.05). Agonistic interactions occurred more often between NON-aggressor and HAR-recipient birds than other categories on days 22 and 23 (p<0.05). HAR-broilers showed no behavioral differences when compared to NON-broilers after 2 days; thus, a similar acclimation period is required before using body-worn sensors to evaluate broiler welfare without altering behavior.

Keel bone fractures affect egg laying performance but not egg quality in laying hens housed in a commercial aviary system

The aim of this study was to investigate the effect of keel bone fracture (KBF) severity and healing activity on individual productivity of laying hens. Focal hens (75 Lohmann Selected Leghorn (LSL), 75 Lohmann Brown (LB)) were housed alongside non-focal hens in 10 identical pens containing a commercial aviary system (15 focal hens per pen). Eggs of focal hens were identified by orally administering a dye on 3 consecutive days, resulting in a hen-specific color pattern in the yolk. Eggs were collected at 7 time points (37 to 61 weeks of age; WOA) for 5 d to determine individual laying performance and to assess egg quality. Radiographs were performed to score KBF severity on a continuous scale. Healing activity was scored as inactive, healing, or fresh. Linear mixed effects models were used for statistical analyses. We found an association between KBF severity and reduced egg laying performance with increasing age (P = 0.005). At 37 WOA, egg laying performance was similar across KBF severities, whereas at 61 WOA, performance in hens with the highest observed KBF severity was 16.2% lower than in hens without fractures. Hens with fresh fractures had a lower performance than hens with healing and inactive fractures at 37 WOA but higher performance at 61 WOA (P = 0.02). Egg quality parameters were not affected by fractures but were associated with an age × hybrid interaction (egg mass: P = 0.039, shell breaking strength: P = 0.03, shell width: P = 0.001). In conclusion, hens could maintain high performance irrespective of fracture severity until shortly after peak of lay, but seemed to redirect available resources towards fracture healing if a fresh fracture was present. At the end of lay, the negative effect of KBF fracture severity on individual production amplified indicating that hens were no longer able to cope with the physiological challenge of a fracture.

Free-range laying hens: using technology to show the dynamics and impact of hen movement

Free-range laying hens are provided with the opportunity to access various structural areas, including open floor space, feed areas, water lines, next boxes, perches, aviary tiers, winter gardens and ranges. Different individual location preferences can lead to the development of hen subpopulations that are characterised by various health, welfare and performance parameters. Understanding the complexity of hen movement and hen interactions within their environment provides an opportunity to limit the disadvantages that are associated with housing in loose husbandry systems and aids in decision-making. Monitoring hen movement using modern technologies such as radio-frequency identification (RFID), optical flow patterns, image analysis and three-dimensional (3D) cameras allows the accumulation of big data for data mining, clustering and machine learning. Integrating individual-based management systems into modern flock management will not only help improve the care of under-performing hens, but also ensure that elite hens are able to use their full genetic potential, allowing an ethical, sustainable and welfare friendly egg production. This review highlights the dynamics and impact of hen movement in free-range systems, reviews existing knowledge relevant for feeding hens in non-cage systems, and outlines recent technological advances and strategies to improve the management of free-range laying hens.

The effect of perch access during pullet rearing and egg laying on physiological measures of stress in White Leghorns at 71 weeks of age

Egg laying strains of chickens have a strong motivation to perch. Providing caged chickens with perches allows them to perform their natural perching behavior and also improves their musculoskeletal health due to exercise. Little is known about the effect of perch access for hens on physiological measures of stress. Our hypothesis was that denying chickens access to perches would elicit a stress response. The objective of this study was to determine the effect of perch access during all or part of life cycle on physiological homeostasis in caged 71-wk-old White Leghorn hens. A total of 1,064 chicks were assigned randomly to cages with and without perches (n = 14 pullet cages/perch treatment) on day of hatch. As pullets aged, chicks were removed from cages to provide more space. At 17 wk of age, 324 chickens in total were assigned to laying cages consisting of 4 treatments with 9 replicates per treatment. Treatment 1 chickens never had access to perches during their life cycle. Treatment 2 chickens had access to perches only from 17 to 71 wk of age (laying phase). Treatment 3 chickens had access to perches only from hatch to 16.9 wk of age (pullet phase). Treatment 4 chickens always had access to perches during their life cycle. At 71 wk of age, chickens were sampled for measurement of plasma catecholamines (epinephrine, norepinephrine, and dopamine) and corticosterone; blood serotonin and Trp; fluctuating asymmetry of shank length and width; and adrenal weight. Only shank width differed among treatments. Chickens with previous exposure to perches during the pullet phase had wider shanks than chickens without access to perches (P = 0.006), suggesting that early perching promoted skeletal development. These results suggest that a stress response was not elicited in 71-wk-old White Leghorn hens that always had access to perches compared with hens that never had access to perches during all or part of their life cycle.

Noncaged laying hens remain unflappable while wearing body-mounted sensors: Levels of agonistic behaviors remain unchanged and resource use is not reduced after habituation

Unique markings or body-mounted sensors facilitate data collection from individuals in large groups of similar-looking conspecifics but may have unintended consequences on behavior. A wireless sensor attached to the back of laying hens via a harness has been developed to monitor space use and activity. Prior to collecting experimental data, effects of the sensor on resource use and social interactions were assessed. Four rooms of 135 hens each were weighed and 10 hens/room were randomly fitted with sensors at 11 wk of age (0 d). Instantaneous scan samples recorded the number of hens (SEN: sensor-wearing hen, and NON: hen without sensor) using resources (feeder, water, nest box, perch) every 5 min over 24 h on -5 d, -4 d, -2 d, -1 d, 1 d, 2 d, 4 d, 8 d, and 16 d. Logistic regression determined that SEN feeder use was less on 1 d and 2 d and more on 16 d than NON feeder use. The SEN water use was reduced only on 1 d. The SEN nest box use increased on 1 d, 2 d, and 16 d. The SEN perched more on 1 d, 2 d, and 4 d, and less on 8 d. Initial resource use was affected by wearing a sensor, but by 16 d, all resources were used similarly or more by SEN than NON. No difference in BW was observed on 17 d, suggesting that long-term resource use was not affected. No differences were observed among the number of agonistic observations -5 d, 8 d, and 16 d. With the exception of SEN hens acting as aggressors toward NON hens, agonistic interaction types occurred close to expected proportions. These factors indicate that hens habituate to wearing sensors within 2 wk.