It has been hypothesized that frustration may arise when one hen sees another dustbathing but her own motivation to dustbathe is thwarted by the limited space provided for more than one bird to dustbathe at once. The hypothesis was based on the fact that hens in a group usually synchronize dustbathing, such that when one starts to dustbathe, she will be joined by others due to their own motivation to dustbathe. Thus, the aim of the study was to evaluate the effect of social stimuli on dustbathing motivation. Hens were housed on one of two floor types: a wire floor (litter deprived), or a floor covered with wood shavings and peat (undeprived). The hens were then prevented from dustbathing as they were exposed one of three stimuli: (1) the sight of other hens dustbathing, (2) the sight of a dustbath that no hen is using, or (3) the sight of a dustbath only. Afterwards, the test hen was allowed to dustbathe. Regardless of deprivation state, hens walked more and spent more time facing the stimulus in (1) than in (3). When not deprived, they walked more in (1) than in (2). When hens were given access to litter after the stimulus test, their subsequent dustbathing behaviour was unaffected by the type of stimuli. The authors suggested that there was some importance in allowing the test birds to join the dustbathing birds, theorizing that the subtle effects of social stimuli on dustbathing motivation may have been masked by the effects of long litter deprivation in their study. Therefore they repeated the experiment, but with shorter litter deprivation times and shorter stimulus exposures, and the test hen was allowed to join the dustbathing hens afterwards. As well, only stimuli (1) and (2) above were used. The authors found more displacement preening and less time facing the stimulus in (1) than in (2) in the second experiment, but dustbathing behaviour was still unaffected by the previous social stimuli. To summarize, dustbathing behaviour of test hens was not affected by seeing other hens dustbathing, but increased walking and displacement preening indicated a possible change in the movement of test hens observing other dustbathing hens.