HomeArticlesHistory & Culture Take a close look next time you take a box of eggs from the supermarket shelf. Do you know where or how your eggs were produced? Read on to learn more about battery farming and the story behind your eggs. Origins of domesticated chickensThe domestic chicken came from the Jungle fowl, originally found in Sri Lanka, India, and south-east Asia. Some 5,400 years ago, DNA analysis and carbon dating show the creation of the domestic chicken through selective breeding of red jungle fowl.1 Now, there are hundreds of different breeds of domestic chicken in the world.Overall, there are two types of farmed chickens - for eggs, and for meat. A wild jungle fowl may produce less than ten eggs per year. Thanks to a particular mutation, domestic egg laying chickens can lay one per day, all year round. Most egg laying chickens are slaughtered at around 16 months when production becomes less reliable.2 The issue on many people’s minds is how the chickens live first.What is battery farming?Early in the 20th century, egg farming became intensive when chickens started being housed in wire cages indoors. This was more efficient. No more predation by roaming predators. Droppings fell cleanly through the wire to land in collection trays. The birds ate food fortified with vitamins to replace those obtained by foraging and sunlight. Controlled temperatures and restricted movement meant food was directly converted into eggs. And huge numbers of chickens were stacked in cages in just one shed. This was battery farming, and it made eggs abundant and cheap.But in battery farms hens are packed closely in cages, unable to stretch their limbs. Eventually, a rise in public concern for animal welfare, as well as research, led to a 2012 ban in battery farming in Europe. And this trend is being mirrored elsewhere. Advisory non-profit Egg Farmers of Canada have committed to phase out battery farming by 2036.3 In the USA, in 2017 several major chains including McDonalds, Nestle and Subway announced they would sell products made with only cage-free eggs.4Legislation against battery farmsNonetheless, there is no ban on caged farming overall. The EU permits enriched cage systems, where the cage must contain a nest, a perch, claw shorteners, an amount of litter for pecking and scratching, and 750 cm square of floor space per hen.5 These cages allow chickens to carry out natural behaviours. But some people argue this is still not enough.Why isn’t all egg farming cage-less?Caged farming has gained a reputation for being cruel and inhumane. Yet other types of housing - indoor barns, free range - also show problems, and these may simply stem from our domestication of the chicken. Here are a few reasons why cage-less farms aren’t the simple solution they may seem:Feather pecking: Though this may sound simply annoying, severe feather pecking is a serious issue in hen farming. Birds develop exposed bald spots, injuries, and even cannibalise each other to death. It’s difficult to control in a large, uncaged flock - a study estimated some 65 percent of UK free-range flocks showed evidence of severe feather pecking.6 Research is investigating if pecking props or lighting can reduce hen aggression, but the issue has been studied for years without easy answers.Injury risk: Domestic chickens are comparatively clumsy, heavy birds compared to their sleek jungle relatives. Their keel bones, an extension of the breastbone, are weakened by continuous egg laying, which requires calcium to be directed away from bones to egg shells. Keel bone injuries can occur in about 36 percent of birds in enriched cages, and 86 percent in free range systems. Hens naturally want to perch, but injuries can occur when they dismount.7 Hen flocks can also crowd, trample and smother each other if frightened.8Disease risks: Standing in dirty litter raises the risk of diseases, parasites, and dirty eggs. Droppings from migrating birds can cause avian influenza outbreaks in free-range flocks.9Logistical issues: Changing large-scale farming methods takes time and money. Hens that have grown up in cages cannot simply be set loose in another system, and cage-free farming can only accommodate two-thirds or fewer birds by comparison.Where next for egg farming?Buying free-range instead of caged eggs can seem an easy option to show support for animal welfare. The price difference is small compared to that of meat. The mental image of hens living permanently indoors, inside small wire environments is easy to picture and easy to dislike. The US food chains recognise this which is why they have declared support for cage-free eggs, despite that, only 8 percent of the 300 million laying hens in the USA are currently cage-free.10According to Dr Victoria Sandilands, a poultry behaviour expert at Scotland’s Rural College, the unanswered question is how to balance out people’s needs, and animals needs while preserving the environment. As Dr Sandilands says, “The advantages of egg production are that eggs are very healthy for you and producing eggs is probably more environmentally friendly than producing some types of meat.” Because of this environmental edge on other proteins, it looks as if eggs are here to stay. Listen to our podcast episode with Dr Sandilands here:You can also download the FoodUnfolded Podcast on Apple Podcasts and Spotify.But while the issues are not black and white between eggs from caged hens versus cage-less, the choice remains up to you.Do you prefer free-range eggs? Let us know in the comments below!