Spontaneous Play in Broiler Chickens at Two Weeks of Age

Abstract

Provision of environmental enrichment in the form of elevated platforms promotes expression of natural behavior such as play and contributes to better welfare in commercial broiler chicken rearing facilities. The majority of the supporting literature utilizes experimentally manipulated stimulated play as the preferred method of data collection for play behavior. This study focused alternatively on observing spontaneous play to determine if there was a treatment effect on natural expression of target behaviors. Flocks of Ross 708 broiler chickens were randomly assigned to either a barren control house which mirrored traditional commercial rearing methods or an experimental platform house that included elevated platform perching structures as novel environmental enrichment. Recorded video data was collected for 5 distinct dates from 4 camera locations, 2 each along the walls and in the center of the houses at 8am, 12pm, 4pm, and 8pm. Target play behaviors included Run, Jump, Frolic, Spar, Worm Chase, and Worm Run. For analysis, worm behaviors were combined into a single Object Play category. Videos were observed in a single randomly assigned quadrant for the first 10 minutes other than a few specified exceptions. Data was entered into the BORIS behavior recording software and extracted for statistical analysis in RStudio via several negative binomial generalized linear mixed models. No significant main effect of treatment was observed on overall play (P = 0.922) between enriched and control houses. A treatment and time interaction was detected for Overall Play (P = 0.031), Frolic (P = 0.009), and Run (P = 0.053) indicating that time of day had an impact on the observed effect of treatment. Interactions were also found for location and treatment on Spar (P = 0.002) and for Time and location on Frolic (P = 0.072) suggesting that location of observation may impact treatment effect and time of day could impact behavior frequency based on location respectively. An effect of time on play behavior was found for Overall Play (P < 0.016), Spar (P = 0.001), and Object Play (P = 0.024) with birds showing greater frequency of play earlier in the day than in the afternoon. Overall Play (P =0.018), Run (P =0.001), and Object Play (P = 0.002) all took place more in the center of the houses than along the walls. A treatment effect was observed for Object Play (P = 0.006), indicating elevated platforms may have increased the frequency of this target behavior. While an overall treatment effect of elevated platforms on spontaneous play was not detected, several target behaviors were influenced by their provision. Important considerations for future welfare studies were revealed, such as careful selection of time and location for play observation. Spontaneous play was determined to be a viable subject for future observation, specifically for those interested in naturally occurring behaviors.