The transportation stage mainly considers the transportation of feed, and the transportation mode is mainly road transportation. The damage caused to the surrounding environment of the road during the transportation process, the feed loss generated during the transportation process and other service costs (such as: high-speed fees, refueling fees, repair costs, etc.) are not considered, and only the exhaust emission during the vehicle transportation process is considered. When using this dataset for Life Cycle Assessment purposes, users should strictly focus on the emissions from road transportation of feed to layer retail farms. It is important to note the exclusion of damage to roads, loss of feed during transportation, and additional service costs from the data. Data users should ensure methodological consistency by applying the same criteria to similar processes being assessed and by taking into account the specific time frame and locations of the field studies conducted (2014-2015, multiple locations in China). The data is specifically tailored for emission analysis and should be used in conjunction with other datasets to provide a comprehensive environmental impact assessment.