Frequent Visits to an Outdoor Range and Lower Areas of an Aviary System Is Related to Curiosity in Commercial Free-Range Laying Hens

Abstract

Individual hen preferences to spend time at particular locations within a free-range aviary system and relationships with temperament is relatively unknown. Hens (n = 769) from three commercial flocks were monitored with Radio Frequency Identification technology to determine time spent on the range, upper and lower aviary tiers, and nest boxes. Prior depopulation, novel arena (NA) and novel object (NO) tests assessed exploration and fearfulness. During early life; more time on the lower tier was associated with more lines crossed in the NA test (p < 0.05). No other evidence suggested preference during early life was related to fear or curiosity. More time on the range and lower tier were associated with heavier pre-ranging body weight and gain (p = 0.0001). Over the hens’ whole life; time spent on range and lower tier was associated with approaching the NO (p < 0.01). More time spent on the upper tier was associated with less time near the NO and fewer lines crossed in NA (p < 0.01). The relationships during early and whole life use of space and some potential indicators of fearfulness were inconsistent and therefore, no strong, valid, and reliable indicators of hen fearfulness such as freezing were identified.

Relationship between Range Use and Fearfulness in Free-Range Hens from Different Rearing Enrichments

“…In contrast with the minimal impacts of rearing enrichments, outdoor rangers were found to be less fearful than the indoor hens across the OFT (both observer and automated measures) and ET, although not TI. Previous studies have also found lower-ranging hens to be more fearful [ 5 , 14 , 22 , 32 , 33 ], but not all tests across all studies reveal differences, with the TI duration showing a negative correlation with the range use in some studies [ 32 , 54 , 55 ] and no relationship in others [ 5 , 14 , 56 ]. Behavioural tests on the same hens do not always correlate and show the same differences, which is likely related to different specific aspects of the traits they are measuring.…”

“…The exposure to the range itself may then improve the adaptability of the birds or habituate them to new stimuli and, thus, decrease their fear with the increasing range use. Range use itself increases over time [ 22 , 53 ], and thus, while there may be some effects of underlying behavioural traits on the initial range access (Campbell et al, unpublished data), these traits may be modified by experiences across the lay cycle. However, the direction of the relationship between fearfulness and range use is not clear from this study, and further research applying fearfulness tests both prior to and following range usage may confirm the causality.…”

“…Rozempolska-Rucinska et al [ 21 ] used computer tracker software to analyse the behavioural reactivity of hens based on the head and tail movements in the presence of novel objects and classified shy/bold hens. Kolakshyapati et al [ 22 ] tracked hens’ movements in a novel arena using ANYmaze software, which automatically classified locomotion around the arena. Thus, automated computer-vision movement tracking might reveal behavioural differences during tests beyond what is detected during manual live or video observations.…”

Preparing for life : effects of environmental choice and change during rearing on adaptability in laying hens

“…The hens given a Multi-choice environment at week 5 made the most visits, as birds from all four pens were seen outside, suggesting higher optimism or seeking. It has been suggested that more curious hens would be more likely to use an outdoor range (Kolakshyapati et al 2020). Usage of an outdoor range is important from a production perspective, since the positive welfare impact of the range, such as reduced risk of feather pecking outbreaks, depends on hens using the range (Nicol et al 2003).…”

Commercial layer hybrids kept under organic conditions: a comparison of range use, welfare, and egg production in two layer strains

“…It is believed that selection of modern commercial strains for production traits lead to associated changes in birds’ fearfulness and ability to cope in novel environments, affecting how they utilize outdoor areas ( Rodenburg et al, 2008 ; Campbell et al, 2016 ; Kolakshyapati et al, 2020 ). Outdoor environments expose birds to potentially stressful situations including weather (rain, wind, temperature extremes), parasites, disease, and predation ( Lay Jr et al, 2011 ; Sossidou et al, 2011 ).…”