Even though the contribution to greenhouse gas emissions by the poultry industry as a percentage of the total emission from the agricultural sector is lower compared to other protein production industries, the scale and rate of growth of the poultry industry means that environmental sustainability must be considered. While there are many factors which impact the emission intensity of a poultry unit, gut health is undeniably linked to the health and welfare of the birds, which in turn improves parameters such as mortality and carcass rejection. If incremental reductions in emissions can be realised throughout the industry, these will multiply to deliver sizable returns.