Effects of different nest designs on nesting behaviour in broiler breeders

Floor eggs are a common issue in broiler breeders flocks, which are unwanted for two reasons: higheconomic costs and reduced animal welfare. The extra costs are caused by an increase of manual labourrequired, in addition to a reduced saleability and hatchability of floor eggs. The welfare of floor laying hensis reduced as the housing, in terms of nest attractiveness, is suboptimal. The goal of this study was toinvestigate which nest design is preferred by broiler breeder hens to lay their eggs. In a relative preferencetest four nest designs were provided to six groups of 100 females housed with 8 males during ages 20-33weeks. The four designs had the following characteristics: nest with a partition wall, nest with a subtle airflow inside created by a ventilator under the nest, nest with wooden walls and control nest. Eggs per nestwere collected daily. Videos were made for one day of each pen at ages 24-26 weeks and 27-29 weeksduring 3-5h and 7-9h after lights-on. Behaviour inside and outside the nests was scored continuouslyduring 5 minutes per half hour for point behaviours and scan sampled at a 10 minute interval for eventbehaviours. At 32 weeks of age the most preferred nest in each pen was closed to observe subsequentpreference. We found a relative preference for the nest with wooden walls compared to the other nestdesigns as more eggs, nest inspections and nest entrances were recorded for that nest. Signs of crowdingwere recorded inside the nest with wooden walls in the form of increased aggression, displacement andpiling behaviour. After closing the nests with wooden walls, the hens laid their eggs in the adjacent nest,independent of the design of this nest.