Welfare and environmental benefits of integrating commercially viable free-range broiler chickens into newly planted woodland: a UK case study.

摘要

The commercial, welfare and environmental impacts of rearing small colonies of free-range chickens in newly planted woodland at two sites in the UK, during the first 2 years of the enterprise, were investigated. Newly planted rather than established trees were used so that commercially viable species could be planted in a way that would suit the management of the chicken enterprise, and small colonies were used so that farmers wishing to diversify could buy into the system progressively. It was anticipated that marketing a high specification product would provide an immediate income, whilst waiting for the future investment in trees to grow. A split plot design was used at each site to investigate the effect of tree provision compared to conventional pasture plots on a range of production and welfare variables. The design also allowed for comparison of two chicken densities. Our measures of welfare included chicken mortality and morbidity, leg health and ranging behaviour, whilst production measures included growth rate, feed conversion and cost of production. Environmental impacts were investigated by examining the effects of chicken presence and density on the growth of the trees, the existing vegetation and groundwater quality. Results for the first 2 years of tree growth showed that the presence of young trees did not improve the measured welfare or production variables at either site compared to pasture range. Tree growth was acceptable by commercial standards and was not affected by chicken presence. Chicken presence and density had inconsistent effects on the composition of the vegetation, but did not result in significant changes to the amount of bare ground at either site. There were no significant changes in the concentration of nitrate, ammonium and phosphate in surface or ground waters attributable to the presence of chickens at the population densities used in the experiment. The experiment yielded important information on the wider aspects of management and production of free-range broilers, including the effects of season, weather conditions and leg health on ranging patterns. It is likely that an impact of trees on welfare and production will become apparent over the next 3-5 years of the enterprise with the increased growth of trees..