This piece by Dr Richard Murphy, Research Director at Alltech Bioscience Centre, provides new insights into the specific and reproducible effects of MRF supplementation on the composition of the bacterial community as a whole. By making changes in the overall microbial diversity within the gut, we can aim to repair and rehabilitate the gut microflora, which can lead to reductions in pathogen load, enhance the gut’s resistance to pathogen colonisation and reduce the abundance of antibiotic-resistant strains. Improving the understanding of these comprehensive changes is now key in the poultry industry.