ABILITY OF LAYING HENS TO NEGOTIATE HORIZONTAL PERCHES AT DIFFERENT HEIGHTS, SEPARATED BY DIFFERENT ANGLES

1. This paper describes how birds move between horizontal perches at d ifferent heights with different angles separating them, using the time to complete the task and the number of birds failing to indicate abil ity. 2. For the first experiment, 4 groups of 15 birds (ISA Brown) wer e subjected to each of the experimental treatments (using three perche s with angles of 0 degrees (horizontal control), 30 degrees, 45 degree s or 60 degrees between them). The birds were required to move upward between the perches for each treatment and then to move downward betwe en the perches, as a second part of the experiment. 3. Birds moving up between the perches took significantly longer at 60 degrees than at a ny other angle. No birds failed to complete the task. 4. For birds mov ing downward between the perches, the median time to complete the task increased significantly with angle. Furthermore, the number of birds failing to complete the task increased with angle. 5. A second experim ent was conducted to test whether the vertical or horizontal component of distance affected birds' ability to negotiate perches separated by different angles. 6. For the second experiment 4 groups of 10 Lohmann Brown laying hens were subjected to each of the following treatments: two horizontal perches separated by 30 degrees or 60 degrees and eith er directly, horizontally or vertically separated by a set distance of 50 cm. Birds were required to move both up and down between perches. 7. Birds negotiated horizontally-separated perches more successfully a t 30 degrees than at 60 degrees. However, when the vertical distance b etween the perches was 50 cm there was no significant difference in th e ability of birds to move downward at 30 degrees or 60 degrees. For b irds moving upward, 60 degrees was easier to negotiate than 30 degrees . 8. The vertical and horizontal separations, as well as the different angles affected the ability of birds to move between perches. There n as a general decreasing trend in ability with increasing vertical sepa ration between perches. 9. The findings are important in terms of arra ngements of perches to improve bird welfare. To minimise the risk of i njury, the angle between perches at different heights should be no mor e than 45 degrees, and the horizontal and vertical distances between t hese perches minimised, to allow the birds to be able to move downward s more easily.