This document contains Bo Weidema’s comments on the public-review version of the LEAP guideline on greenhouse gas emissions and fossil energy demand from poultry supply chains. It presents proposed revisions to definitions, modelling choices and technical guidance. It is a review submission, rather than the final guideline or a study reporting a poultry product footprint.
A central concern is whether the modelling approach matches the intended use of the assessment. Weidema argues that decision support for improvements requires information about the consequences of those improvements. He therefore proposes consequential modelling and system expansion to address co-products, rather than relying on attributional allocation rules. These are the author’s recommendations in the consultation.
The comments discuss manure, energy recovery and poultry processing in detail. They call for consistent treatment of displaced products and associated emissions. An extended example examines how demand for one meat cut can affect production and consumption of other cuts. The proposed revisions also distinguish joint production, where outputs cannot vary independently, from combined production.
Further comments seek clearer terminology for system boundaries, unit-process inventories, packaging and greenhouse gas metrics. Weidema also notes that secondary data can sometimes be better than primary data and recommends best estimates with corresponding uncertainty instead of blanket worst-case assumptions. The document is useful for understanding the methodological issues raised during this review. It does not establish which proposals were accepted in subsequent LEAP guidance.
