Behaviour, welfare, and tibia traits of fast- and slow-growing chickens reared in intensive and free range systems
The behaviour, welfare, and tibia characteristics of fast- and slow-growing chickens were evaluated in free-range and intensive production systems. A total of 720 birds of three strains were subjected to these systems after 21 days of rearing under the same intensive environment. Each treatment was replicated six times with 20 birds in each replicate. Data were collected for welfare aspects, including feather condition, footpad, hock joint and tonic immobility, behavioural features, especially feeding or foraging, sitting, walking, scratching, pecking and dust-bathing, and tibia characteristics, including weight, length, width, medullary canal diameter and robusticity index (4 - 8 weeks). Production system had significant effects on all welfare and behaviour aspects of the birds. However, tibia characteristics were not influenced by production system, except for medullary canal diameter. The strains differed significantly in welfare, tibia characteristics and behaviour. For example, the slow-growing strains had better feather condition, footpad and hock joint scores. Significant interactions of strain and production system were noted for all characteristics. It was recommended that Rhode Island Red chickens could be raised under either production system without compromising their welfare or causing adverse effects on leg health.