Determination of range enrichment for improved hen welfare on commercial fixed-range free-range layer farms

Abstract

An observational study on range enrichment was conducted on three commercial fixed-range, free-range layer farms comprising four flocks in South Australia (flock sizes ranged from 3000 to 11700 hens). Two strategies were compared; a ‘standard’ Control treatment, typical of the type of range used in the commercial industry and a highly ‘enriched’ treatment. Both treatments were implemented on the same range with no subdivisional fences. The highly enriched side of the range incorporated shade shelters, alongside a continuum of additional enrichment structures (e.g. dust baths, peck objects and hay bales). Range treatments were investigated to determine the effects on motivating hens to use the range more effectively, and their potential to lead to a decrease in abnormal behaviours, such as injurious feather pecking and cannibalism. Additionally, two farms with high levels of tree coverage were also observed. Farms were visited monthly for 6 months. At each visit several measures were recorded live: the numbers of hens out on the range, location of hens on the range and plumage score of birds outdoors and indoors. Enrichment structure utilisation on the range was measured via video recordings and continuous counts of the number of hen visits to enrichment structures within 1 h. It was found that more hens used the ‘enriched’ side of the range, in comparison with the ‘standard’ Control range treatment (P ≤ 0.01). Overhead cover provided by constructed shelters and dust bathing pits were instrumental in enticing birds out onto the range (306 ± 27 s.e.m. and 366 ± 24 s.e.m., average number hen visits). Hay bales were also highly utilised (116 ± 14 s.e.m., average number hen visits), even though the hen numbers attracted to the hay bales were not as high as shelters and dust baths. It was also observed on one property that natural cover provided by trees attracted the greatest number of hens (1652 ± 358 s.e.m., average number of hen visits). Prevailing weather conditions and the age of the flock strongly influenced the number of hens utilising the range outdoors. Furthermore, hens outside on the range had better plumage scores with lower feather loss and decreased areas of bare skin compared with birds scored in the shed.

Peer Review #1 of "Application of open field, tonic immobility, and attention bias tests to hens with different ranging patterns (v0.1)"

“…The extent of damage was confounded with range use for the selected hen groups making it difficult to determine the role of feather damage in the levels of fear, and the causative relationship with range use. Previous studies have found better plumage condition in hens scored while outdoors compared to hens scored while indoors (De Koning et al, 2018), better plumage in those hens that ranged farthest (Chielo et al, 2016) or better plumage in hens tracked to range more frequently (Rodriguez-Aurrekoetxea and Estevez, 2016). But not all studies have found associations between ranging and plumage condition (Hartcher et al, 2016;Larsen et al, 2018).…”

Peer Review #3 of "Effects of outdoor ranging on external and internal health parameters for hens from different rearing enrichments (v0.2)"

“…The hens that ranged the most showed the best plumage coverage which provides further support to previous research. Several studies have demonstrated better plumage in individuals, or flocks that show more frequent use of the outdoor range (De Koning et al, 2018;Lambton et al, 2010;Mahboub et al, 2004;Rodriguez-Aurrekoetxea & Estevez, 2016), or who range farthest when outdoors (Chielo et al, 2016). It might be that hens outdoors are able to or are motivated to engage in more foraging compared with hens indoors (Campbell et al, 2017) where a lack of foraging is often redirected to feather pecking, causing plumage damage (Bestman et al, 2009;Gilani et al, 2013;Rodenburg et al, 2013).…”

“…Individually tracked free-range hens that use the outdoor area more, show less feather damage than hens that prefer to spend time indoors (Mahboub et al, 2004;Rodriguez-Aurrekoetxea & Estevez, 2016). Similarly, opportunistic scoring of hens on the range has shown better plumage condition compared with hens scored in the shed (De Koning et al, 2018) and better plumage in hens that ranged farther (Chielo et al, 2016). Outdoor ranging hens or hens that have access to a range area show comparatively reduced footpad dermatitis (Heerkens et al, 2016;Rodriguez-Aurrekoetxea & Estevez, 2016) and range use keeps toenails shortened (Campbell et al, 2017;Yilmaz Dikmen et al, 2016).…”

Case Study of an Automatic Enrichment Device for Laying Hens on a Free-Range Laying Hen Farm

“…occurred on those days. Observations took place at eight times during production when the hens were 30,34,38,42,46,50,54, and 58 weeks of age (LW).…”

“…Many studies have shown that feather pecking and cannibalism are influenced by various factors (e.g., genetics, group size, diet composition or structure, and light regimens) [16][17][18][19][20][21]. The provision of suitable litter [22][23][24][25][26] and enrichment material [27][28][29][30][31][32][33][34] has been found to reduce feather pecking and cannibalism. Red jungle fowl are known to spend a large proportion of their daytime activity on ground scratching (60%) and pecking (34%) on forest soil (i.e., foraging) [35].…”