A new study published in Royal Society Open Science today reveals striking trade-offs when it comes to different methods of egg production.
Using UK data, the study compared several possible scenarios for the egg industry, including shifts to barn, free-range and organic systems, while keeping egg output constant. The authors find that although cage-free systems may align more closely with public concern for hen welfare, they may also require larger hen populations and could increase environmental pressures. Shifting to an entirely free-range and organic method of egg production from a business-as-usual scenario, for example, would raise emissions by 60% while almost doubling land occupation. These results highlight the need to integrate environmental outcomes when guiding future transitions toward non-cage egg production, the authors say.
“Our research highlights the importance of considering animal welfare, environmental impact and food production together when shaping the future of egg farming,” says author Dr Harriet Bartlett (Oxford Martin Programme on the Future of Food). “Being aware of these tricky trade-offs will help us make better decisions for the environment and animal welfare in the future,” she adds.
“Being aware of these tricky trade-offs will help us make better decisions for the environment and animal welfare in the future”
Dr Harriet Bartlett
The global food supply chain creates 26% of human-caused greenhouse gas emissions and is responsible for 78% of eutrophication (excess nutrient enrichment of water), and 32% of terrestrial acidification (soil damage). Global production of eggs is a key driver of these impacts, having quadrupled over the past 50 years.
Meanwhile, advocacy for a wholesale transition away from cage-based husbandry systems has increased. “While this movement is driven by important concerns around farm animal welfare, differences in production performance among husbandry systems could lead to unintended outcomes,” says lead author Oliver Martinic, an independent researcher based in Croatia.
“This is not to say concerns around eggs from caged chickens can or should be dismissed or that we should return to restrictive caged systems. But we want farms and consumers to be aware of all the potential impacts when it comes to the methods by which we produce our food,” says Dr Bartlett. “By taking a broader view, we can find the best ways to balance these trade-offs as we pursue a more sustainable global food system.”
The authors also found a significant rise in mortality for 100% free-range and organic systems. However, they acknowledge the data used in the study were collected between 2009-10, and progress has been made since then. “This is an important limitation, and we are transparent about it in the paper. However, these data remain the most comprehensive available for laying-hen production systems in the UK,” says Martinic.
The research highlights important trade-offs between different types of egg production, but it is not calling for a return to caged farming. The researchers recognise that the transition towards cage-free production is important for improving animal welfare. However, their findings also suggest that transitioning to cage-free systems without also improving factors such as mortality and feed efficiency is likely to increase environmental impacts. The challenge is therefore to develop production systems that combine high standards of animal welfare with improved animal performance and lower environmental impacts.