the agricultural and industrial production systems from which raw materials for feed inputs are derived; the processing of raw materials; the production of feeds; the production of chicks; farm-level material and energy use at pullet and layer facilities; shell egg processing and packaging; egg breaking and processing; and all transportation stages up to the processing facility gate (Fig. 1). This analysis did not include emissions associated with the production and maintenance
of infrastructure such as machinery and buildings (these typically make trivial contributions to supply chain emissions, since they must be amortized against total production over their anticipated lifespan (years) e for example, see Ayer and Tyedmers 2009).