Increased duration of laser environmental enrichment increased broiler physical activity and pen-wide movement without altering tibia measurements

Abstract

Inactivity and leg disorders negatively impact broiler welfare. Enrichment designed to increase barn complexity may encourage physical exercise. The study aim was to implement a second-generation laser enrichment device, previously shown to increase broiler activity, for extended periods of time and to measure behavior and tibia quality. A total of 1,360 Ross 708 broilers in 40 pens of 34 were assigned to laser enrichment or control (no laser enrichment) for 49 d. Seventy focal birds were randomly selected on d 0 for individual behavior analysis. Laser-enriched birds were exposed to 6-min laser periods 4 times daily. A 3-min novel object test was performed on all pens and tonic immobility was induced on 1 bird/pen on wk 1 and 6. Focal bird time budget and walking distance and pen-wide laser-following behavior and movement were obtained during laser periods d 0 to 8 and 1 d/wk through wk 7. Right tibias were collected from focal birds on d 49 for dual energy x-ray absorptiometry and bone breaking analysis. Time spent active during laser periods was increased on d 3, 6, and 8 and wk 2 to 3 in laser-enriched vs. control focal birds (P=0.04). Time at the feeder was increased in laser-enriched focal birds on d 0, 3 to 4, and 8 and wk 2 and 4 (P < 0.01). Distance walked during laser periods was increased in laser-enriched focal birds on d 1, 3 to 5, 8, and wk 2 compared to the control (P < 0.01). Pen-wide movement was increased on d 0, 2, 4 to 8, and wk 1 to 5 and 7 in laser-enriched vs. control birds (P < 0.01). More laser-enriched broilers were within 25 cm of the novel object at 1 min 30 s than the control (P=0.03), and latency to approach the novel object was reduced in both treatments at wk 6 compared to wk 1 (P < 0.01). Tonic immobility duration was increased by 123 s on wk 6 compared to wk 1, regardless of treatment (P < 0.01). Daily laser enrichment for extended periods increased bird activity without inducing fearfulness or altering tibia measures.