François Djitie Kouatcho

Balance between feed efficiency and bone health in free-range broilers reared under global warming conditions

n order to meet the meat products needs of an ever-growing world population, standard chickens have undergone considerable growth, breast yield and feed efficiency improvements over the last few decades. Cumulated with intensive production conditions, this selection resulted in birds now reaching a weight of 2 kg in just 5 weeks. Despite this increase in productivity and the success of poultry meat, criticisms on animal welfare and product quality abound. Indeed, fast-growing chickens move around considerably less than slow-growing chickens, lying still for a substantial part of the time during rearing. This results in poor bone mineralisation in birds and thus to  musculoskeletal disorders and less robust animals.
The project is part of a drive at improving the sustainability of poultry farming systems to promote the transition towards more agroecological production systems. Feed efficiency, which depends on both animal capacity and feed composition, is a key element in this economic and environmental pillars of sustainability. Mastering bone health is a key factor in broiler welfare. However, efficient birds are also those spending less energy in physical activity, which is detrimental for bone health. To adapt systems to this transition by adopting feed and/or selection strategies, it is essential to gain a better understanding of the birds' ability to adapt and the balances between functions.
The aim of this project is to model how feed efficiency and bone tissue robustness interact in summer range conditions, in the context of global warming. Measuring biomarkers of bone health will enable assessment of the impact of access to the open air on efficiency and health parameters under summer conditions and will guide further research on the breeding and feeding strategies best suited to hot weather conditions. The study could suggest new selection criteria of interest for the development of existing prediction models.