The laying hen 

Hen eggs are a reproductive body laid by the female that consist of an ovum surrounded by nutrient material, layers of membrane and a protective outer shell.

Today's egg laying hens are descended from the Red Jungle fowl (Gallus gallus) of Asia which lays around 60 eggs a year. Modern breeds of domestic hen have been selectively bred to lay over 300 eggs a year.

Selective breeding for high egg production has resulted in distinct strains of birds for egg laying and for meat production. Birds of the laying strain do not make good meat birds and as a result male birds of the laying strain, who neither lay eggs nor produce meat efficiently, are killed when a day old.

Female hens in egg farms suffer from a range of welfare problems and restrictions during their lifetime. When the productivity of the flock falls the hens are sent for slaughter and are quickly replaced with more profitable animals. Laying hens are normally only kept for one year before they are slaughtered - their natural lifespan is around seven years. This slaughter of "spent" hens takes place even in free range systems.

The egg industry

There are over 29 million hens in egg-laying flocks in the UK who produce 8,643 million eggs a year. In 2008, around 58% of eggs produced in the UK were from caged (intensively farmed) hens, 4% from barn systems and 38% from "free range" systems, including around 5% from organic systems. In addition, a further 2,133 million eggs were imported into the UK in 2008.

Farming systems for egg-laying hens

Battery Cages
In the UK nearly 17 million laying hens are kept in battery cages which are so small that they cannot stretch their wings, peck, scratch the ground, or perform other natural behaviours such as dust bathing, perching and laying their eggs in a nest.

Battery cages provide a floor space of 550cm² per hen of cage area, equivalent to a piece of A4 paper. A battery cage typically contains four or five hens. The cage floors are sloped up to 21.3% (or 12 degrees) depending on the floor type which may consist of wire mesh. The slope is so that the eggs roll forward for collection by the farmer and puts painful pressure on the hen's toes, causing damage to the bird's feet.

Hens housed in battery cages are susceptible to feather pecking (whereby the hens will attack and peck each other) which occurs in situations of social and physical stress.

Feather pecking has also been described as redirected ground pecking as caged hens are unable to ground peck. Feather pecking leads to feather loss and hens may cannibalise birds with exposed flesh. In an effort to prevent feather pecking farmers debeak the birds (see debeaking).

The lack of exercise and high egg production can lead to brittle bones that are easily broken. The Institute of Food Research in Bristol found nearly 30% of caged birds had broken bones by the time they reached the water bath stunner in the slaughterhouse.

Battery systems are to be outlawed in Europe from 2012, but the so-called 'enriched cages' that will replace them are little better.

"Enriched" Cages
Enriched cages must provide at least 750 cm2 per hen, of which 600 cm2 should be "useable area", the remaining area being shared space for items such as a nest box. Enriched cages should have litter, a claw-shortening device and a perch. The extra space in enriched cages is equivalent to roughly a postcard-sized piece of paper when compared to a battery cage and the facilities provided still deprive the birds of the ability to fulfil their natural behaviours.

Birds in enriched cages have slightly better bone health compared to hens kept in battery cages but their bones are still classed as osteoporotic. Birds in enriched cages are still vulnerable to feather pecking behaviour and are therefore debeaked (see debeaking).

Barn Systems
"Barn" eggs are produced from hens kept in flocks confined to a shed with no access to the outdoors. Hens may be stocked at a density of 12 hens per square metre.

Litter should be provided for scratching and dust bathing but only needs to cover one third of the ground surface. Nest boxes should be provided at 1 nest box for every 7 hens or a communal nest for every 120 hens. Perches should also be provided allowing 15cm of perch per hen.

Hens in Barn systems are debeaked in an attempt to control feather pecking behaviour.

"Free" Range
Birds in free range systems can be stocked at a density of 9 hens per square meter. In addition the hens must have continuous daytime access to open runs that should mainly be covered with vegetation and at a maximum stocking density of 2,500 birds per hectare which equates to 4 square metres per hen.

Birds in free range systems may be debeaked to combat feather pecking.

Debeaking
Hens' beaks have an extensive nerve supply but to combat feather pecking famers debeak them. During debeaking or "beak trimming" a red-hot blade sears off the end of the birds' beak. Debeaking occurs in caged, barn and free range systems. Debeaking is a serious mutilation which results in a significant reduction in preening and pecking afterwards. This reluctance to use the area after amputation is thought to be guarding behaviour in response to pain and discomfort. As feather pecking occurs among stressed birds unable to fulfil their natural behaviours debeaking adds insult to injury by punishing the birds for the systems they are kept in.

Malignant Tumours
Another welfare problem associated with selectively breeding hens to lay more eggs is the development of malignant tumours of the oviduct. In one investigation, a significant proportion of malignant tumours of the oviduct were identified in 20,000 'spent' layers selected from ten different farms. The researchers concluded, "... the increase in the prevalence of the (magnum) tumour coincides with continued selection of fowl for high egg production".

Slaughter of Spent Hens
Most egg-laying hens in the UK are sent for slaughter after a year of egg production.

The hens are caught and bundled into crates before being transported by lorry to the slaughterhouse. One study found that at the time of catching and crating, levels of the stress hormone corticosterone in battery hens were 10 times higher than normal. Around 30% of battery hens arriving at the slaughterhouse are reported to have at least one freshly-broken bone.

The number of freshly broken bones in live birds prior to slaughter and the number of old healed breaks had been described as "unacceptably high".

"Spent" hens are considered to be of low value and after slaughter their flesh will be used in chicken soups, pastes, pies, pet food, etc.

Slaughter of Cock Chicks
For every hen hatched for egg laying there is a cock chick that is killed because he is the wrong strain to be raised for meat. Common slaughter methods include gassing, neck dislocation and the 'macerator', a device that shreds chicks alive. Over 40 million day old chicks are killed in hatcheries in Britain every year.

Food vs. Feed
Hens laying eggs don't produce food, they wasteit! It takes approximately 1.8 kilograms (4 pounds) of grain to produce just 12 eggs.

This is because the conversion of crops by farm animals into food for humans is grossly inefficient.

Environmental Impact
Ammonia is a common by-product of animal waste. Ammonia gas escaping into the atmosphere is a serious pollutant linked to acid rain. As part of its Integrated Pollution Prevention and Control strategy Defra (the Department for Environment, Food and Rural Affairs) states that egg production units "affect the environment by the production of ammonia, dust, odour, noise etc and through emissions of nutrients and metals associated with manure, used litter and dirty water. The effect of these could include acidification, eutrophication, damage to ecosystems and build up of substances in soil and reduction of amenity."21

Human Health
Eggs are a source of salmonella food poisoning. Advice from the Government's Food Standards Agency (FSA) warns that "some eggs contain salmonella bacteria, which can cause serious illness, especially among elderly people, babies, toddlers, pregnant women and people who are already unwell."

Go Egg Free
You don't need to eat eggs to have a healthy balanced diet. It's very easy to make egg-free cakes, quiches, mousses and other traditionally "eggy" dishes. Most vegan cookbooks contain plenty of such recipes.