Scientific briefing on laying hen welfare
There are more than 300 million laying hens in the European Union, over three quarters of whom are currently housed in battery cages. Laying hens are chickens which are primarily reared to produce eggs, rather than meat.
Chickens are complex creatures and display a wide range of behaviours, such as foraging, dustbathing, nesting and preening. In the wild, mother hens normally live in small groups with their broods of chicks, spending much of their day roaming their territory in search of food.
Some behaviours are particularly important for hen welfare. Scientific studies have shown that hens are strongly motivated to build nests prior to laying their eggs and will work hard to gain access to a nestbox before laying. Hens clean themselves by dustbathing – they burrow out a hollow in the ground and flick dust over themselves, shaking it through their feathers to remove old oils and mites. Hens who are prevented from dustbathing and then allowed to do so spend much more time dustbathing than normal. As night approaches, chickens are strongly motivated to find a safe place to perch and rest.
Exercise is also very important for hen welfare, particularly in modern commercial breeds of laying hens that have been selected for increased egg production, which diverts their bodies' calcium reserves from bone development to egg production. Consequently, modern laying hen breeds may be much more prone to osteoporosis and bone fractures – a condition made worse by lack of exercise.
Hens reared in barren battery cages in the European Union have just 550 cm² per hen in which they spend their entire adult lives, living in barren cages with each cage holding several other birds. These cages are stacked in rows, often several tiers high, in large windowless sheds. The tiny available space is less than the size of an A4 sheet of paper per hen and provides no space for exercise or even to stretch or flap their wings. There is no litter in which to dustbathe, and no perch. The European Union agreed in 1999 to ban barren battery cages, with this ban due to come into force in 2012. Even though the production method will be illegal in the EU at that time, eggs and egg products from hens confined in barren battery cages could potentially be imported from outside the EU after that date.
The 'enriched' cage will still be allowed after 2012. This cage provides a small amount more space and height (a minimum 750cm² floor space per hen, of which 600cm² per hen must be 'usable'), and provides some additional facilities such as a nest area, a small amount of litter material and low perches. Enriched cages are still close-confinement systems, allowing hens very little space to exercise. Scientific evidence has shown that much more space is needed by hens to perform most basic behaviours, such as turning around, wing stretching and preening. The litter area is inadequate to satisfy the hens' needs for dustbathing and the low perches in enriched cages may not be perceived by hens as safe roosting areas. Consequently enriched cages cannot fully meet hens’ behavioural needs.
Free-range and barn housing systems can provide well for hens' needs, providing much more space to nest, exercise, dustbathe and forage. These housing methods are much more extensive and allow for the whole range of hens’ behaviours to be performed. Well managed free-range systems encourage the majority of hens to range outdoors during the day. Some farmers have developed free-range systems further, for example planting trees and low cover to promote hens' use of the whole outdoor area.
For a detailed analysis of the scientific evidence comparing the welfare implications of caged versus cage-free systems, see CIWF’s latest report ‘Alternatives to the barren battery cage for the housing of laying hens in the European Union’ which can be downloaded from the Good Eggs website.
