LAUSR

Abstract Conventional broiler breeders are severely feed restricted during the rearing period, resulting in an unfulfilled behavioural need for performing feeding behaviour and likely in a sensation of hunger. As a response to the feed restriction, behavioural changes have been observed, including increased foraging and drinking and reduced resting behaviour. This study aimed to investigate effects of four dietary treatments, differing in fibre types and content, on behaviour of broiler breeder females during rearing. The dietary treatments were: 1) standard feed (Control), 2) standard feed diluted with insoluble fibres (Insoluble), 3) standard feed diluted with both insoluble and soluble fibres (Mixed) and 4) standard feed supplemented with maize silage (Roughage). The amount of the different diets allocated was adjusted for the birds within different treatments to achieve the growth rate recommended under commercial conditions. In total, 1200 female breeder chicks of the genotype Ross 308 were housed in 24 pens from day-old to 19 weeks of age, six pens of 50 birds per treatment. Birds were observed every second week during three different periods of the day relative to feeding time: 1 h before, 1 h after and 5 h after. During each period, the observer noted the behaviour of focal birds (n = 6/pen) for 2 min. Body weight was monitored weekly. For each behaviour the likelihood of whether it was performed and the duration (only including those observation periods where the behaviour was performed) during the observation periods were analysed. Compared to the Control birds, Mixed birds were less likely to forage (P = 0.001) and walk (P