Effects of nest quality and other cues for exploration on pre-laying behaviour

Abstract

Persistence of searching behaviour during the pre-laying period in the presence of a suitable nest site may indicate that hens are strongly motivated to perform this behaviour. This was investigated by observing behaviour in environments with or without a suitable nest site and other cues for exploration. Eleven hens were tested individually in four environments using a 2 × 2 experimental design: presence or absence of litter and presence or absence of an exploratory walkway. Comparing pre-laying behaviour between environments with unlittered and littered nest box, longer durations of pre-laying behaviour (151(±20) vs. 110(±13) min, ANOVA, df = 1,27; P < 0.05) and searching phase (32(±6) vs. 19(±3) min; P < 0.05) were observed. Hens also showed more searching behaviour (26(±5) vs. 14(±4) min; P < 0.01) and performed more nest examinations (27(±8) vs. 10(±3); P < 0.01) in environments with a littered nest box. More entries were recorded into unlittered nest boxes (11(±2) vs. 7(±1); P < 0.05), though of a shorter mean duration (8(±2) vs. 16(±6) min; P < 0.01). The duration of the searching phase was longer in environments with than without the walkway (35(±6) and 16(±4) min respectively, P < 0.01). More searching behaviour (28(±5) vs. 13(±3) min; P < 0.001) and more nest examinations (8(±2) vs. 4(±1); P < 0.01) were recorded in environments with the walkway. It is suggested that in the absence of an appropriate nest site the motivation to perform searching behaviour remains high. However, when compared to barren environments, environments that provide cues for exploration result in the motivation to perform pre-laying behaviour being more fully expressed.