FACTORS AFFECTING THE USE OF PERCHES IN CAGES BY LAYING HENS

1. Three experiments were carried out with ISA Brown laying hens house d in individual cages with softwood perches of rectangular cross secti on fitted across the width of each cage, to investigate factors affect ing the tendency of hens to lay their eggs from the perches and to use perches at other times. These factors were perch width and angle and method of perch introduction. 2. In experiment 1 there were 4 treatmen ts. Perches were 38 or 60 mm wide; half of each width were flat and ha lf were fixed at 8 degrees, parallel to the slope of the floor. In 2 s imilar trials (with 48 and 44 birds respectively, equally divided betw een treatments) birds were moved to experimental cages already fitted with perches. Birds with 38 mm, sloping perches laid less than one thi rd of their eggs from the perch (31% and 9% in the two trials) while t hose with the other designs laid more than 80% from the perch. Narrow sloping perches were not otherwise aversive and there was no consisten t variation between treatments in total time perching. 3. In experimen t 2, 32 birds were allowed to start laying on the floor of the experim ental cages then perches were introduced at 24 weeks with 8 birds on e ach of 4 treatments: 50 mm perches fixed flat and 38 mm perches fixed flat, and at 5 and 10 degrees respectively. Only 27% of eggs were laid from the perches with no variation between treatments either in this behaviour or in total time perching. 4. Experiment 3 provided 24 of th e birds from experiment 2 with double-length perches to determine whet her they showed preferences for the design features under consideratio n. Either half the perch length was flat and half sloping at 10 degree s or half was 38 and half 50 mm wide. Again a relatively low proportio n of eggs was laid from the perches (18%) and birds showed no signific ant preference for different perch designs as indicated by either how much they perched or where they perched. 5. These results suggest that both perch design and the way pullets are introduced to perches influ ence the proportion of perch-laid eggs. They confirm that in some circ umstances laying from perches can be a serious problem, but that in ot her circumstances incidence can be reduced to a manageable frequency. Perches may therefore be practical in commercial production without in creasing the number of cracked eggs. The results are also likely to be applicable in cages with other facilities including nest boxes.