Differences in feed formulation are more determining of life cycle environmental impacts in U.S. egg production systems than are resource use efficiency and housing system choice
Bibliographic record
Abstract
Improvement of environmental sustainability outcomes is a priority for the American egg industry. This analysis provides an updated, ISO 14044-compliant life cycle assessment of the American egg supply chain, including differentiation between conventional cage and cage-free housing. The assessment was based on primary data collected directly from U.S. egg value chain participants, describing operations in 2019. Contrary to expectations based on the literature, estimated environmental impacts in both cage-free pullet and layer systems were found to be lower than those of caged systems, despite the demonstrably lower farm-level resource-use efficiency and hen productivity achieved in these systems. In some cases, impacts were up to 48 % lower per tonne of eggs produced in cage-free systems. These differences were instead primarily driven by differences in feed formulations, in particular the reported absence of animal-derived products in feed formulated for cage-free systems. Substitution of the caged feed formulation for the cage-free formulation, under the assumption of nutritional equivalency, led to substantial reductions in the environmental impacts of egg production in caged systems. The findings of this analysis clearly demonstrate the critical role of feed production in shaping environmental outcomes of U.S. egg production systems. Moving forward, it is clear that innovative feed strategies developed through the lens of a life-cycle thinking-based approach must be explored to support sustainable development of the U.S. egg industry. • LCA models of American caged and cage-free egg production were developed. • Primary data were collected from feed mills, and pullet and egg producers. • Resource-use efficiency was generally better in caged than cage free systems. • Environmental impacts per functional unit were generally lower in cage free systems. • Lower impact feed may offset impact increases from lower resource-use efficiency.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".