Laying hens usually select an elevated position for resting at night-time. A previous study showed that the position a hen takes during resting was affected by perch material, most probably due to its thermal conductivity. The aim of the present study was to analyse the effect of perch surface temperature on resting behaviour and resting comfort in laying hens. In each of two identical trials, three groups of five Lohmann Selected Leghorn hens were housed in each of three compartments in turn (n = 30 birds in six groups). Compartments were equally equipped with one smooth, round galvanised steel perch of 34 mm external diameter. The surface temperatures of perches were controlled by passing water through them, giving temperatures of 15 °C, 18 °C (room temperature) and 28 °C respectively in the three compartments. Hen behaviour was observed at night-time by investigating the proportion of active behavioural patterns and resting (standing or sitting), either with 'head forward motionless and neck withdrawn' or 'head tucked backwards into feathers above wing base or behind a wing.' The number of hens perching and the time spent perching were unaffected by perch temperature. Hens' resting postures, however, were strongly influenced. On the warmest perch, hens rested more with their head forward in a standing position and showed more active behavioural patterns compared to both cooler perches (P < 0.001). On the cooler perches, hens rested more with their head covered by feathers in a sitting and standing position (P < 0.05). Our data show that perch temperature strongly affects laying hens' resting behaviour. In this context, hens are confronted with arising trade-offs between thermoregulatory adjustment of behaviour, optimisation of energy budget, restful roosting and vigilance behaviour.

Resting on perches is an important behaviour for laying hens. However, perches in laying hen husbandry systems are associated with health problems which may result from inadequate perch designs. The aim of this study was to focus on particular behavioural patterns shown by laying hens on different perches during night-time in order to test whether perching behaviour may provide information on the suitability of a particular perch design. A total of 60 Lohmann Selected Leghorn hens were kept in six compartments over two identical trials. Hens were randomly offered nine round perches, which differed in material (wood, steel, rubber cover) and diameter (27, 34, 45mm) for one week each. Duration of resting, standing, preening and frequencies of balance movements and comfort behaviours shown by individual hens on each perch were recorded throughout one night (10.5h) on day six of each observation week. Balance movements decreased with increasing perch diameter (P<0.001) and appeared less on rubber perches compared to wood and steel (P<0.05). On steel perches, hens rested longer with their heads tucked backwards into their feathers (P<0.001) and less with their heads forward with neck pulled back compared to wood and rubber perches (P<0.001) irrespective of perch diameter. Standing was shown less often on steel compared to wood or rubber perches (P<0.001). Our data provide evidence that a detailed analysis of hens’ perching behaviour can give important information on the suitability of a perch design related to diameter and material. In this context, balance movements may be the most sensitive indicator of the suitability of a perch design with respect to stable footing on perch, whereas resting position and standing on perches are likely to be related to thermoregulatory adjustment in behaviour.

BACKGROUND:Domestic animals and their wild relatives differ in a wide variety of aspects. The process of domestication of the domestic guinea pig (Cavia aperea f. porcellus), starting at least 4500 years ago, led to changes in the anatomy, physiology, and behaviour compared with their wild relative, the wild cavy, Cavia aperea. Although domestic guinea pigs are widely used as a laboratory animal, learning and memory capabilities are often disregarded as being very scarce. Even less is known about learning and memory of wild cavies. In this regard, one striking domestic trait is a reduction in relative brain size, which in the domesticated form of the guinea pig amounts to 13%. However, the common belief, that such a reduction of brain size in the course of domestication of different species is accomplished by less learning capabilities is not at all very well established in the literature. Indeed, domestic animals might also even outperform their wild conspecifics taking advantage of their adaptation to a man-made environment.In our study we compared the spatial learning abilities of wild and domestic guinea pigs. We expected that the two forms are different regarding their learning performance possibly related to the process of domestication. Therefore wild cavies as well as domestic guinea pigs of both sexes, aged 35 to 45 days, were tested in the Morris water maze to investigate their ability of spatial learning.RESULTS:Both, wild cavies and domestic guinea pigs were able to learn the task, proving the water maze to be a suitable test also for wild cavies. Regarding the speed of learning, male as well as female domestic guinea pigs outperformed their wild conspecifics significantly. Interestingly, only domestic guinea pigs showed a significant spatial association of the platform position, while other effective search strategies were used by wild cavies.CONCLUSION:The results demonstrate that domestic guinea pigs do not at all perform worse than their wild relatives in tests of spatial learning abilities. Yet, the contrary seems to be true. Hence, artificial selection and breeding did not lead to a cognitive decline but rather to an adaptation to man-made environment that allows solving the task more efficiently.