Effects of increasing environmental complexity on the physical activity of broiler chickens

Increasing the level of physical exercise in broilers has been indicated to improve leg condition. We attempted to stimulate locomotor and foraging activities by adding environmental complexity to experimental broiler pens. We hypothesised that adding barriers between food and water, and stimulating foraging behaviour would increase level of physical activity. To test this hypothesis, 1800 male broilers (1-day-old) were divided into 40 groups of 45 birds (10 birds/m(2)). Each group was assigned to one of four treatments in a randomised block design with 10 replicates as follows: barrier treatment (13) contained three barriers placed between the drinkers and the feeder. The light treatment (L) consisted of brightly coloured moving lights projected on the pen floor for four 1 h periods per day throughout rearing. Whole wheat was dispersed on the floor from day 8 to day 17 in the wheat treatment (W). Control birds (C) were maintained under standard management practices. Five focal birds per pen (200 birds total) were observed by focal sampling during 3 min per week, from 1 to 6 weeks of age. The behavioural. data were analysed using repeated measures ANOVA. B birds spent 9.7 +/- 2.1% of time perching, spent less time lying than L and W birds (P < 0.05) and changed their feeding and drinking patterns (fewer observation periods containing bouts of both eating and drinking than C birds, P < 0.05). Neither L or W treatments enhanced foraging and locomotion. However, L birds spent more time eating than C birds (P < 0.05). The behaviour of W birds did not differ from the controls. Increasing environmental complexity modified the behaviour and the organisation of feeding and drinking patterns in B and L birds. Perching behaviour was high in the presence of barriers, which may have beneficial effects on the welfare of the birds since it stimulated greater variety of motor patterns. Effects of moving lights and scattering wheat in the litter were unclear or non-existent. However, further studies need to be conducted to determine if this type of enrichment could help to improve animal welfare. (C) 2002 Elsevier Science B.V. All rights reserved.