Ranging behaviour of commercial free-range laying hens

Chielo, Leonard Ikenna, Pike, Tom and Cooper, Jonathan (2016) Ranging behaviour of commercial free-range laying hens. Animals, 6 (5). ISSN 2076-2615

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Simple Summary: Commercial free-range production has become a significant sector of the fresh
egg market due to legislation banning conventional cages and consumer preference for products
perceived as welfare friendly, as access to outdoor range can lead to welfare benefits such as greater
freedom of movement and enhanced behavioural opportunities. This study investigated dispersal
patterns, feather condition and activity of laying hens in three distinct zones of the range area; the
apron area near shed; enriched zone 10–50 m from shed; and outer range beyond 50 m, in six flocks
of laying hens under commercial free-range conditions varying in size between 4000 and
24,000 hens. Each flock was visited for four days to record number of hens in each zone, their
behaviour, feather condition and nearest neighbour distances (NND), as well as record temperature
and relative humidity during the visit. Temperature and relative humidity varied across the study
period in line with seasonal variations and influenced the use of range with fewer hens out of shed
as temperature fell or relative humidity rose. On average, 12.5% of the hens were observed on the
range and most of these hens were recorded in the apron zone as hen density decreased rapidly
with increasing distance from the shed. Larger flocks appeared to have a lower proportion of hens
on range. The hens used the range more in the early morning followed by a progressive decrease
through to early afternoon. The NND was greatest in the outer range and decreased towards the
shed. Feather condition was generally good and hens observed in the outer range had the best
overall feather condition. Standing, pecking, walking and foraging were the most commonly
recorded behaviours and of these, standing occurred most in the apron whereas walking and
foraging behaviours were recorded most in the outer range. This study supported the findings of
previous studies that reported few hens in the range and greater use of areas closer to the shed in
free-range flocks. This study suggests that hens in the outer range engaged more in walking and
foraging activities and showed signs of better welfare than those closer to the shed.
Abstract: In this study, the range use and behaviour of laying hens in commercial free-range flocks
was explored. Six flocks were each visited on four separate days and data collected from their
outdoor area (divided into zones based on distance from shed and available resources). These were:
apron (0–10 m from shed normally without cover or other enrichments); enriched belt (10–50 m
from shed where resources such as manmade cover, saplings and dust baths were provided); and
outer range (beyond 50 m from shed with no cover and mainly grass pasture). Data collection
consisted of counting the number of hens in each zone and recording behaviour, feather condition
and nearest neighbour distance (NND) of 20 birds per zone on each visit day. In addition, we used
techniques derived from ecological surveys to establish four transects perpendicular to the shed,
running through the apron, enriched belt and outer range. Number of hens in each 10 m × 10 m
quadrat was recorded four times per day as was the temperature and relative humidity of the outer
range. On average, 12.5% of hens were found outside. Of these, 5.4% were found in the apron; 4.3%
in the enriched zone; and 2.8% were in the outer range. This pattern was supported by data from
quadrats, where the density of hens sharply dropped with increasing distance from shed.
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Consequently, NND was greatest in the outer range, least in the apron and intermediate in the
enriched belt. Hens sampled in outer range and enriched belts had better feather condition than
those from the apron. Standing, ground pecking, walking and foraging were the most commonly
recorded activities with standing and pecking most likely to occur in the apron, and walking and
foraging more common in the outer range. Use of the outer range declined with lower temperatures
and increasing relative humidity, though use of apron and enriched belt was not affected by
variation in these measures. These data support previous findings that outer range areas tend to be
under-utilized in commercial free-range flocks and suggest positive relationships between range
use, feather condition and increased behavioural opportunities and decline in the use of range in
cold and/or damp conditions.

Keywords:ranging behaviour; free-range laying hens; feather condition; enrichment; ecological survey, NotOAChecked
Subjects:D Veterinary Sciences, Agriculture and related subjects > D300 Animal Science
D Veterinary Sciences, Agriculture and related subjects > D328 Animal Welfare
Divisions:College of Science > School of Life Sciences
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ID Code:23064
Deposited On:25 Apr 2016 12:31

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