Organic and free-range eggs carry a carbon footprint roughly twice that of eggs from caged hens, according to a study in Royal Society Open Science. The reason is efficiency: free-range flocks need more birds and more feed to produce the same quantity of eggs. UK-wide, a fully organic system would emit about 2.3 million tonnes of CO2 equivalent per year, versus 1.2 million tonnes for a fully caged system. The study is based on 2009-2010 British farm data, so it does not capture newer feed technology or management changes. It also does not account for pesticide use or biodiversity. The authors and critics note that carbon is only one environmental metric. Organic systems may look better on pollution, soil, and animal welfare, even if they emit more per egg. For anyone tracking food-related emissions, the key takeaway is that single-metric comparisons can mislead. A fuller life-cycle view that includes water, land, and biodiversity is needed before using these numbers in labels or procurement decisions.
