Our aim is to build a first catalog of the chicken intestinal metagenome. We will sequence DNAs extracted from samples of caecal microbiota of chic kens representing the high population diversity in production farms and in INRA experimental facilitie s. Using this catalog we will study the characteristics of the chicken intestinal microbiota a in terms of gene content and taxonomical composition according to production type, breed, nutrition, rearing conditions and other parameters recorded, with a special focus on antibiotic resistance genes and health- and digestion-related genes.