Dustbathing in modified battery cages: Is sham dustbathing an adequate substitute?

Abstract

Dustbathing in poultry is a highly motivated behaviour which will occur even in the absence of salient stimuli, as ‘sham’ or ‘vacuum’ dustbathing. Some designs of modified cages for laying hens contain dustbaths. The aim of this study was to determine the extents to which conventional and modified cages meet the hens' behavioural need to dustbathe. We assessed the frequency and duration (in 36 cages) and behavioural elements (in 50 cages) included in dustbathing sequences. The location in the cage of dustbathing bouts was recorded to investigate the effects of nest boxes and dustbaths. Bout frequency was not significantly different between cage types, but bouts were shorter ( p = 0.02) in conventional cages than in modified cages. Relatively few dustbathing bouts were performed in dustbaths when these were available (mean 8.3% and 26.7% of bouts with restricted and free access to dustbaths, respectively), with most bouts performed by the feed trough and including billraking at the feed. Dustbathing occurred on only 8.5% of all visits to the dustbath with foraging, resting and standing alert being common activities in dustbaths. There was little difference between treatments in the behavioural components included in dustbathing bouts, although for example, rubbing and pecking were more common on the dusty substrate than on the wire floor. The results are discussed in terms of strength of dustbathing motivation.