Individual variation in how hens interact with a dust substrate

This paper re-examines in further detail the findings of an experiment reported previously by Laine et al. (2009). Briefly, Laine et al. (2009) preference tested laying hens (n = 15) for their choice between social contact (a familiar, subordinate hen) and a dust substrate (a tray of peat moss) in a Y-maze apparatus. Although the dust substrate was much preferred to social contact, it was observed that hens differed in how they interacted with the dust substrate in the Y-maze when they chose it. To examine individual variation further, each hen was classified as one of three types, based on the proportion of Y-maze trials in which the hen chose the Y-maze arm containing dust and commenced a dustbathing bout. A dustbathing bout was defined as commencing when the hen first rolled onto her side. Hens which commenced a dustbathing bout on >85% of dust-chosen trials were defined as “dustbathers”, while hens which commenced a dustbathing bout o