Hens are motivated to dustbathe in peat irrespective of being reared with or without a suitable dustbathing substrate

Abstract

Birds usually dustbathe in litter, but in the absence of this they sham dustbathe. The question addressed in this study was whether laying hens, Gallus gallus domesticus reared without litter and used to performing sham dustbathing consider this to be ‘real’ dustbathing and are satisfied with this or, if given the opportunity, would choose to dustbathe in a functional substrate? We used the push-door as the operant method to quantify motivation to dustbathe in 28 adult laying hens from four different treatments. The treatments reflected different previous experiences of litter and were based on the time period during rearing that birds had been housed with access to peat: (1) never, (2) early rearing, (3) late rearing and (4) always. All hens were deprived of peat before the start of the test, which was carried out when the birds were adults, and they were tested every fifth day in a series of trials with increasing resistance of the push-door. A hen was removed from the test when she no longer successfully pushed through the door. The results showed that there was no difference between treatments in the weight of doors that hens pushed open to gain access to peat. This implies that sham dustbathing is not satisfying or perceived as normal dustbathing, even for birds that developed dustbathing behaviour in the absence of litter because birds that had no previous experience of peat were as motivated to work to gain access to this substrate as birds used to dustbathing in peat.