Dark brooder pullets are less active than Non-brooder pullets, but show similar level of synchronisation at the resource areas

Abstract

Maternal care in commercial chickens can partially be replaced with dark brooders that offer heat and a dark area to rest and possibly avoid negative social interactions. Previous research has established the positive effects of dark brooders on reducing disturbance during resting in young pullets and injurious pecking in pullets and laying hens, which could reduce overall activity levels. The objective of this study was to employ precision livestock farming techniques to compare the overall activity levels and behavioural synchrony at resources in pullets reared with dark brooders until 41 days of age and those reared with whole house heating. Four brooder treatments, varying in size (Small/Large) and deployment method (Raised/Fixed), which could have implications for commercial use, were employed. Activity of the whole pen floor area and behavioural synchrony in drinker and feeder areas were automatically assessed over a 12-hour photoperiod at 10 and 60 days of age. Pixel change detection gauged overall activity across the pen, while an object detection model evaluated pullet behavioural synchrony. The analysis revealed increased activity levels in non-Brooder pullets compared to those in most Brooder treatments at both 10 and 60 days of age. However, no significant differences in behavioural synchrony were observed between Brooder and non-Brooder pullets. The underlying mechanism of dark brooder’s effects on the activity levels and behaviour synchrony remains unclear, but the observed reduction in activity levels in brooded pullets likely corresponds to increased resting behaviour and reduced injurious pecking. Furthermore, it is noteworthy that only a small percentage of pullets (up to 57.14%) were observed to use the resources simultaneously. This underscores the importance of conducting additional research to delve into the effects of resource allocation on both behavioural synchrony and activity levels in pullets. We observed minimal differences in the behaviour of pullets raised under different brooder types, suggesting that the simplest (Small-Fixed) brooders may be suitable for commercial use.