A novel environmental enrichment device increased physical activity and walking distance in broilers

Abstract

Modern broilers are selected for fast growth and a large proportion of breast tissue, contributing to a top-heavy phenotype, leg disorders, and inactivity as birds reach market weight. Therefore, the objective was to motivate broilers to move through environmental enrichment. A total of 1,200 Ross 308 broilers were housed in pens of 30 for 6 wk: 600 birds were exposed to a novel laser enrichment device (LASER) and 600 were control. Each device projected 2 randomly moving red laser dots onto the floor 4 times/day for 4-min “laser periods.” Seven LASER and 7 control pens, with 5 focal birds/pen (n = 70), were randomly selected to be video-recorded day 0 to 8 and once weekly for the remainder of the trial. Videos were analyzed to measure broiler time-budget and behaviors such as latency to feed and distance walked during laser periods. Focal birds were gait scored weekly on-farm. A test of the human-approach paradigm was carried out on weeks 1 and 6 on all pens. LASER birds were more active on days 0, 1, 3, 4, 5, 7, and 8, moving 254% more on day 7 ( P ≤ 0.05). Time spent active was increased in LASER treatment by 114% on week 2; 157% on week 3; 90% on week 4; and 82% on week 5. LASER birds spent more time at the feeder on days 0, 1, 2, 5, 8, and on weeks 1 and 5, with 84% more time at feeder than control on day 5 ( P ≤ 0.05). LASER birds walked further during laser periods on day 0 to 8, reaching 646.5 cm greater (day 1), and on weeks 2, 3, 4, and 5, with an increase of 367.5 cm on week 2 ( P ≤ 0.05). Over week 1 to 6, 60.54 ± 7.4% of focal birds in the laser treatment were at the feeder during or within 5 min following laser periods. The laser enrichment device was successful in stimulating broiler physical activity and feeding, and did not negatively impact walking ability.

Laser Enrichment Device Stimulates Broiler Laser-Following Behavior While Increasing Individual Bird Locomotion and Pen-Wide Movement

“…The red-colored bird was used for broiler home pen behavior analysis, the bluecolored bird for walking distance analysis, and remaining focal birds were used for gait scoring and tibia collection. This means of identifying focal birds has been used by the authors previously (Meyer et al, 2020) and proved an effective way to recognize birds on video that did not alter inter-bird behavior (did not induce pecking, aggression, injury).…”

“…Ten laser enrichment devices, previously described by Meyer et al (2019Meyer et al ( , 2020, were placed over 20 pens; each device was designed and calibrated to cover two adjoining pens (approximate floorspace of 5.95 m 2 ). The enrichment device consisted of two independent red 650 nm lasers contained within a 20.5 by 20.5 cm metal box with a glass bottom mounted on a custom-designed structure made of three wooden beams (2.4 m height) raised above the pens.…”

“…Trained observers watched the red-colored focal bird (n = 14) during the 4-min laser periods on d0-9, 16, 23, 30, and 37, and categorized bird behavior continuously using a pre-determined ethogram (Meyer et al, 2020) for both frequency and duration (s; Table 1). Duration was converted to percent of time spent on each behavior per 4-min period.…”

“…The distance walked by the blue-colored focal bird (n = 14) was measured over the 4-min laser periods (d0-9, 16, 23, 30, and 37), using methods described and validated in Meyer et al (2020). Briefly, the focal bird movement was recorded by tracing the bird's route on screen using a clear sheet protector, and subsequently measured using the custom ruler tool on Adobe Photoshop (Adobe Systems Inc, San Jose, CA, U.S.).…”

“…A laser enrichment device was implemented in a previous study using 1,200 Ross 308 broilers fed a simple practical diet by the current authors with the hypothesis that insect-sized, red moving laser dots would visually motivate broiler exercise throughout grow-out. The device proved capable of increasing broiler locomotion through wk 5 of life, by up to 157% increased activity (wk 3) and 367.5 cm increased walking distance (wk 2) compared to the control (Meyer et al, 2020). Therefore, the current study objectives were to confirm the ability of the laser enrichment device to motivate broiler activity and feeding behavior, to document effects on pen-wide movement, and to quantify walking ability and tibia quality outcomes.…”