Life Cycle Assessment (LCA) has become more widely and internationally accepted around the world, including in Thailand. The objective of this study is to calculate and identify the amount of greenhouse gas emission in order to provide an environmental profile for the broiler industry. In this study, LCA methodology was applied to chicken feed production for 12 different formulas from 3 participating factories in Thailand. The results of the study reveal that producing one kilogram of chicken feed requires 0.12-0.36 MJ of energy consumption, both in electricity and fuel. In terms of greenhouse gases, the results show the emission of 374-473 gCO(2)eq for broiler feed and 408-454 gCO(2)eq for parent feed. Energyrich and protein-rich ingredients are the main contributors to the greenhouse gas effect, accounting for 87-96%. Those used in a factory, such as electricity, water and fuel, are less significantly impactful, or 3-11% of total greenhouse gases on average for all formulas. Grain transportation is also not a prominent contributor to the impact, accounting for less than 3% of total greenhouse gases. This is because the grains are produced domestically in Thailand. Feasible options to reduce greenhouse gas emissions include the replacement of soybeans-a conventional, protein-rich ingredient and the replacement of corn-a typically energy-rich ingredient. The results show that GHGs reduces by 1.67-6.96% when 20% of the soybeans are replaced by cassava leaves and by 12.80-22.77% when replacing 50% of the corn with cassava roots.