Quantifying Nesting Motivation in Domestic Hens

Summary

The fact that laying hens prefer to lay in a nest is not evidence in itself that a suitable nest-site is necessary for the hens’ well-being. Stronger evidence would be found if hens were prepared to pay some cost to use a nest-site. The objective of this study is to quantify the strength of individual hens’ nesting motivation in terms of meaningful measures such as overcoming aversive obstacles, work or time.

To investigate the motivation to gain access to a nestbox, hens were floor housed in groups of four in a pen containing food and water. Access to a nesting pen containing two nestboxes, could be restricted using a number of obstacles such as a narrow gap, a water bath and a swing door. Between trials hens were singly housed in wire-floored cages containing a perch and a nestbox. Results indicate that hens made less entries of longer duration to the nesting pen (Means + s.e in Figures 1 and 3) on treatment days with an obstacle than on control days without an obstacle. There was little disruption of use of the nest box (Figures 2 and 4). Hens that were due to lay made more visits on both control (C Egg) and treatment (T Egg) days (Figure 1), which may indicate greater motivation to explore the whole pen before oviposition.