Taxonomical distribution of the major phyla in the inoculum and gnotobiotic chicken gut at day 9 and day 18. Taxonomical distribution of the major phyla in the inoculum and gnotobiotic chicken gut at day 9 and day 18. The inoculum was derived from 6 healthy feral chickens. Germfree chicks were inoculated on day 3 posthatch and euthanized on day 9 (n = 7) and day 18 (n = 9) posthatch. The five most abundant phyla were Bacteroidetes, Firmicutes, Actinobacteria, Proteobacteria, and Spirochaetes. Milton Thomas et al. mSphere 2019; doi:10.1128/mSphere.00035-19