Evaluation of the effects of cage height and stocking density on the behaviour of laying hens in furnished cages

Abstract

1. Limited information is available on how changes in horizontal and vertical space within enriched or furnished layer cages (as defined by Directive 1999/74/EC) influence hen behaviour. This study evaluated the effects of varying minimum cage heights and space allowances on the behaviour of laying hens housed in furnished cages. It was conducted on two flocks of medium brown hybrid hens housed in furnished cages with access to perches and nest boxes on a semi-commercial scale at ADAS Gleadthorpe. 2. Flock 1 consisted of two layer strains (ISA Brown and Babcock 380), housed at two minimum cage heights (38 and 45 cm) and 5 stocking densities between 609 and 870 cm2/bird, with 12 replicates of each of the 20 strain/cage height/stocking density treatment combinations. Stocking density was varied by varying the number of birds per cage from 10 to 7 in standard full-width cages or housing 7 hens in a narrower cage. As a consequence stocking density, group size and trough width per bird co-varied for 4 out of 5 stocking density treatments. 3. Behaviour of flock 1 was sampled at 33 to 36, 46 and 68 weeks of age. At each age one top-tier, one middle-tier and one bottom-tier cage was sampled for each treatment. 4. Few behavioural differences due to cage treatments were detected. Hens at 870 cm2 had shorter feeding bouts than hens at 609 and 762 cm2. Yawning was more common in the cages with greater cage height. 5. Video recordings of flock 1 examined cage height effects on hens' use of vertical space and provided additional data on stretching and self-maintenance activities. No differences in behaviour between 38 and 45 cm cages were found except that scratching head was more common in cages with greater cage height. 6. Flock 2 consisted of two layer strains (Shaver Brown and Hy-Line Brown), housed at 38 and 45 cm and 609, 762 and 1016 cm2/bird, with 18 replicates of each of the 12 strain/cage height/stocking density treatment combinations. Stocking density was varied by housing 10, 8 or 6 hens in standard full-width cages. Behaviour of flock 2 was sampled at 30, 48, 60 and 67 weeks from video recordings. Three cages per treatment from middle-tiers only were sampled at each age. 7. Hens housed at 609 cm2/hen had the longest mean feeding bout, greater than for hens at 762 cm2/hen but not hens at 1016 cm2/hen. More unsuccessful attempts to reach the feeder and sideways and backwards displacements from the feeder occurred at 762 and 609 cm2/hen than at 1016 cm2/hen. A maximum of 8 hens were observed feeding synchronously. 8. These results suggest that changes in horizontal and vertical space over the ranges we studied had little effect on behaviour other than feeding behaviour. Specifying a minimum useable trough space per hen, rather than calculating feeder space from total length of feeder per cage, irrespective of accessibility, might help avoid crowding at the feeder and associated disturbance of feeding bouts.

Production performance and nitrogen flow of Shaver White layers housed in enriched or conventional cage systems

“…Similarly, bird activity tends to increase with increasing group size when associated with the cage area (Carey et al, 1995;Albentosa et al, 2007), which can be explained by the synchronous feeding of hens (Hughes, 1971). In addition, Matsui et al (2004) and Elson and Croxall (2006) reported a lower feed intake for birds in furnished compared with conventional cages.…”

Perching behaviour and perch height preference of laying hens in furnished cages varying in height

“…In Belgium, for example, certain politicians tried to incorporate a minimum cage height of 50 cm for furnished cages but failed to do so. Although it is known that the behaviour of hens differ when housed at different cage heights (Nicol, 1987;Albentosa et al, 2007), that hens prefer taller cages (Dawkins, 1985) and seemingly are prepared to work to access a high target cage (Albentosa and Cooper, 2005), the specific link between cage height and perching behaviour has, to our knowledge, not previously been studied. The objective of this study is, therefore, to investigate the effect of cage height on perching behaviour and perch height preference in laying hens.…”

Opinion of the Scientific Panel on Animal Health and Welfare (AHAW) on a request from the Commission related to the welfare aspects of various systems of keeping laying hens

“…However, certain behaviours, notably wing flapping and flying, are rarely or never observed in cages, even at low stocking densities Albentosa and Cooper, 2004). There is some evidence from rebound studies to suggest that these behaviours are important (Nicol, 1987) but it seems that they are prevented by spatial restriction, even at allowances that exceed the current recommendation .…”