Does Rearing Laying Hens in Aviaries Adversely Affect Long-Term Welfare following Transfer to Furnished Cages?

Abstract

This study tests the hypothesis that hens that are reared in aviaries but produce in furnished cages experience poorer welfare in production than hens reared in caged systems. This hypothesis is based on the suggestion that the spatial restriction associated with the transfer from aviaries to cages results in frustration or stress for the aviary reared birds. To assess the difference in welfare between aviary and cage reared hens in production, non-beak trimmed white leghorn birds from both rearing backgrounds were filmed at a commercial farm that used furnished cage housing. The videos were taken at 19 and 21 weeks of age, following the birds' transition to the production environment at 16 weeks. Videos were analysed in terms of the performance of aversion-related behaviour in undisturbed birds, comfort behaviour in undisturbed birds, and alert behaviour directed to a novel object in the home cage. A decrease in the performance of the former behaviour and increase in the performance of the latter two behaviours indicates improved welfare. The results showed that aviary reared birds performed more alert behaviour near to the object than did cage reared birds at 19 but not at 21 weeks of age (P = 0.03). Blood glucose concentrations did not differ between the treatments (P>0.10). There was a significant difference in mortality between treatments (P = 0.000), with more death in aviary reared birds (5.52%) compared to cage birds (2.48%). The higher mortality of aviary-reared birds indicates a negative effect of aviary rearing on bird welfare, whereas the higher duration of alert behavior suggests a positive effect of aviary rearing.

Rearing Laying Hens in Aviaries Reduces Fearfulness following Transfer to Furnished Cages

“…The study by Tahamtani et al ( 25 ), using birds that were identical to those used in the current study, indicated that aviary-rearing resulted in birds that displayed more comfort behavior at 19 weeks of age but had higher mortality throughout the production period. Higher expression of comfort behavior in aviary-reared birds suggests that they had better welfare, whereas the greater mortality throughout production suggests the opposite.…”

“…The current study focused on the early production phase soon after transfer to the production facility. Future research could test whether the effect of rearing persists to later stages of development, especially given the previously reported negative effects of aviary rearing on mortality throughout the production phase ( 25 ). Farmers are unlikely to use aviary rearing as a method of reducing fearfulness in laying hens specifically, especially if they should later be used for producing in cages.…”

“…As previously mentioned, the subjects and most of the methods in the current study correspond to Tahamtani et al ( 25 ). However, the methods and results for approach–avoidance behavior are unique.…”

“…Fear responses were evaluated at 19 and 21 weeks of age using the duration of time spent close to a novel object in the home cage. The birds used in the present study are identical to those used by Tahamtani et al ( 25 ). The previous article focused on using undisturbed comfort behavior and alertness in response to a novel object as indicators of animal welfare and not specifically as indicators of fearfulness.…”

Review of rearing-related factors affecting the welfare of laying hens

“…The general activity of floor-reared pullets following transfer to cages is reduced in the first days after transfer relative to cage-reared birds, likely reflecting the greater change that the floor-reared birds were thus exposed to (Craig et al., 1988 ). Another commercial scale study showed that aviary-reared birds exhibited more alert behavior near to a novel object than did cage-reared birds at 3, but not at 5, weeks after transfer (Tahamtani et al., 2014 ). Alert behavior in response to a novel object in the home environment is associated with a positive choice and therefore is an indicator of good welfare in laying hens (Nicol et al., 2009 ; Nicol et al., 2011 ).…”