Sirovnik, J., Euteneuer, P., König von Borstel, U. 2021. An attempt to use sound-imprinting to attract broilers onto elevated platforms for night-time roosting. Applied Animal Behaviour Science 243, 105448.

Welfare of fast growing broilers is often compromised due to leg health issues. A more complex environment such as the provision of elevated platforms facilitates activity and improves leg health in fast growing broilers. Thus, encouraging the use of elevated platforms might further enhance leg health. Chickens are known to follow the mother to the elevated platforms to roost, and if the mother is not in the vicinity the chicks will follow her vocalisations. This study aimed to investigate, whether exposing broiler chickens to a sound before and/or after hatching could be used to manipulate chickens to move onto elevated platforms for roosting. We further aimed to identify the effects of such sound-imprinting on chickens’ leg health. A 2 by 2 factorial design was used, and the chicks were either imprinted on white noise before and/or after hatching or were not imprinted. After seven days of treatment post hatching, speakers installed above the elevated platform played the same recording as used for the sound exposure for 10 min each day. Thereafter, barn lights were turned off for four hours. The sound from above the elevated platform was played to imprinted and non-imprinted chickens. Starting at eight days of age, we weekly recorded the number of birds on the elevated platform before the playback, all changes in position between floor and elevated platform from before to after the playback, and all changes in movements either to or away from the playback source (i.e. speaker) after 10 s of recordings. Furthermore, we assessed gait score weekly and pododermatitis score and breast blisters at slaughter at 42 days of age. Data were analysed with Generalized Linear Mixed Models. Our results show that imprinting (or our attempts thereof) had no effect on the use of elevated platforms as well as on any health score. Additional research needs to identify, if auditory imprinting could be strengthened using visual cues in the sensitive post-hatching period, or if another more natural sound (e.g. a recording of a broody hen) can elicit a stronger imprinting effect.