Prelaying behaviour of laying hens (Gallus gallus domesticus) in different free range settings

The aim of this study was to achieve a better knowledge of prelaying behaviour of laying hens in semi-natural environments. Two experiments (Experiment A and B) with 2 replicates (Replicate 1 and 2) each were conducted. In Experiment A 28 laying hens were kept in a pen without nest access until week 21. From then on they were carried out into a pasture during the day where their prelaying behaviour and their chosen nest sites were observed. In Experiment B from week 21 on the hens additionally had access to chicken coops in the pastures in which they also spent the night. In Experiment A several hens regularly laid in the pen in the evening or during the night whereas in Experiment B most hens used the chicken coop as their nest site. In both experiments the frequencies of resting, exploratory behaviour and foraging in the hour before oviposition declined significantly while the frequency of nest-related behaviour significantly increased. Occurrence of the gakel call declined significantly in the last 5 minutes in Experiment A. Even though the changes in frequencies of the behavioural activities were qualitatively the same in both experiments, exploratory behaviour and the gakel call were at a lower level in Experiment B which might indicate less frustration. Hens in experiment B which had access to litter at any time (the substrate in which they had laid before the experiment started) showed less frustration compared to the hens in experiment A which had access only to natural nest sites in the pastures and which were carried out every morning. This indicates that the nest site and/or the substrate in which the first eggs were laid and/or the handling procedure are of great importance for nest choice and prelaying behaviour. This study reports a qualitative and quantitative description of prelaying behaviour and effects influencing it in different free range settings. The results about the observed behaviour may serve as a basis for comparing and assessing commercial laying nests in respect to their suitability for hens.