Influence of the provision of natural light and straw bales on activity levels and leg health in commercial broiler chickens

The aim of this study was to assess the effect of natural light and straw bales on activity levels and leg health in commercial broiler chickens. Houses containing ∼23 000 broiler chickens were assigned to one of four treatments in a 2 × 2 factorial design. Treatments involved two levels of access to natural light (NL) (present '+NL', or absent '-NL') and two levels of access to straw bales (SB) (present (30/house) '+SB', or absent '-SB'). All houses were windowed and artificially lit, and windows were shuttered where appropriate. Treatments were applied in one of the two houses on each of the two farms, and were replicated over four production cycles. Behaviour was observed in 2 to 6 weeks of…