Using Radio-Frequency Identification Technology to Measure Synchronised Ranging of Free-Range Laying Hens.

Dana Campbell,Geoff Hinch,Brian Horton

doi:10.3390/ani8110210

Dana Campbell, Geoff Hinch + Show 1 more

Open Access

https://doi.org/10.3390/ani8110210

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Abstract

Simple SummaryFree-range laying hens can choose to be indoors or outdoors. Individual hens vary in their ranging choice and this behaviour could also be affected by their flock mates. Radio-frequency identification tracking of individual hens in experimental free-range pens with group sizes of 46–50 hens was used to study flock ranging patterns. Across the day, hens moved through the range pop-holes in the same direction as other hens above levels expected by random chance, termed ‘pop-hole-following’. Hens were also simultaneously indoors or outdoors with other specific hens more often than expected by random chance, termed ‘hen-pair association’. Chicks that were provided variable stimulatory and structural enrichments from 4 to 21 days showed higher pop-hole-following and hen-pair association than non-enriched birds. The individual birds within these small hen groups were behaving primarily as a cohesive flock which has implications for understanding the group-level behaviour of hens. Further research would analyse if similar social movement patterns were present in larger commercial free-range flocks and how early rearing environments may affect adult social behaviour.Free-range laying hen systems provide individuals a choice between indoor and outdoor areas where range use may be socially influenced. This study used radio-frequency identification technology to track the ranging of individually-tagged hens housed in six experimental free-range pens from 28 to 38 weeks of age (46–50 hens/pen). All daily visits to the range were used to study group behaviour. Results showed that 67.6% (SD = 5.0%) of all hen movements through the pop-holes outdoors or indoors were following the movement of another hen (‘pop-hole-following’) compared to only 50.5% of movements in simulated random data. The percentage overlap in time that all combinations of hen pairs within each pen spent simultaneously outdoors or indoors showed a median value of overlap greater than the 90th percentile of random data. Pens housing hens that had been provided variable enrichments from 4 to 21 days (n = 3 pens) showed higher ‘pop-hole-following’ behaviour and a higher percentage of hen-pair association compared to hens reared in non-enriched conditions (n = 3 pens). These results show that birds in each free-range pen were primarily a cohesive flock and early enrichment improved this social cohesiveness. These results have implications for understanding free-range flock-level behaviour.

Highlights

Animals living within groups will typically exhibit both individual behaviour patterns and engage in social interactions resulting in group-level dynamics
Laying hens (Gallus gallus domesticus) are a domesticated gregarious species, and with the increase in alternative cage-free housing systems, hens are often kept in groups of thousands of individuals
There was no effect of early enrichment rearing treatment on the mean number of hours spent There no effect earlydaily enrichment rearing treatment on range the mean number of hours outdoors

Summary

Introduction

Animals living within groups will typically exhibit both individual behaviour patterns and engage in social interactions resulting in group-level dynamics. Behavioural synchrony of a group of intensively-housed animals has been used as both a positive and negative indicator of welfare [4]. Synchrony may facilitate resting [5] and flock-level cohesion may result in an even temporal distribution of birds to optimise use of the available resources. This could include steady transitions between system areas [6] or adjusting egg-laying patterns to ensure nest box availability [3]

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