Don’t put all eggs in one basket! – Insights on husbandry-specific environmental costs of egg production

Over the last years, the consumption of organically produced food has increased rapidly. In 2017, the volume of organic produced food e.g. in Germany was 5.4%. Compared to 2004 (1.7%), the share has more than tripled. The main motivation for people buying organic products is a reduction of pollution, environmental protection and the preservation of biodiversity. Due to the missing transparency of environmental and resource-strategic aspects in the production process, the consumers are currently forced to make the purchase decision based on their personal judgement. With this societal change towards more organic products, it is essential to display the environmental footprint of food production, so that customers can compare goods based on their ecological impact. This research focuses on the environmental and resource-strategic aspects of the egg production. A meta-analytical study based on sixteen pertinent studies on egg production systems and their environmental impact was conducted. The systematic literature research and the basic structure of the elaboration are subdivided into the criteria: method, quantities and monetisation. A first strand of scientific literature defines the methodological aspect of life cycle assessment (LCA) with concentration on ecological and economical aspects of the value chain. Further research is focused on gathering quantities of the ecological impacts of different production systems and specific countries. A third strand of research relates to the monetarisation of damage costs. None of the previously published studies include all three focus areas. Closing this research gap, we combine all these aspects, we define a monetising strategy on the relevant environmental impacts of the main egg production systems (cage, barn and organic rearing) and set a price markup of production-system specific external costs. A conducted qualitative evaluation allows a limitation to four environmental impacts: greenhouse gas, acidification, eutrophication and energy use. In addition, an adapted weighting system is implemented. Weighting studies according to their base country, their actuality and the valued limitations of the research defining three different scenarios as distinguished. For the key scenario, the external costs of the organic production are nearly twice as much compared to the cage-rearing system. Nevertheless, relating the external costs to the different customer prices, the organic production shows the smallest surcharge. While external costs account for 43% of total costs for organic-rearing eggs, the percentage of external costs for cage-rearing eggs adds up to 47% and 60% for barn-husbandry. The still high amount of environmental impacts in organic production can be primarily attributed to the direct distribution of agricultural emissions into the ecosystem. The high degree of automatisation in conventional production through manure belts, air cleaning and indoor keeping is the reason for reduced emission values and larger use of energy resources. For analysing the sensitivity of the results, an extreme value analysis is implemented. The maximum deviation of 10.6% shows a stable calculation of the external costs for eggs. Considering further sustainability aspects, like animal welfare and species-appropriate keeping and the importance of organic labelling, additional research is essential to define the shadow prices of the egg production to full extent.