As a child, we were all told that the hen "gives" you her eggs...

Domestic hens are descended from jungle fowl living in South East Asia. In their natural environment, they live in small groups with a well-defined pecking order. They forage for food, dust-bathe in hot weather, and lay their eggs in a secluded nest. The life of a battery hen is a little different. The natural lifespan of a chicken is about ten years. In a battery cage, she is lucky that she is killed after just eighteen months. Her life starts in an incubator. When she is born, she is sexed. The male chicks are pulled out and either gassed or left to suffocate in a plastic bag.

Alternatively, they may be ground up while still alive to make feed for their sisters. The next stage is to cut off the baby chick's beak with a hot blade: this prevents her from pecking at other hens in the cage later in life. It also results in constant pain and difficulties with feeding.

According to the zoologist Professor F. W. Roger Brambell, "The hot knife used in debeaking cuts through [the] complex of horn, bone and sensitive tissue, causing severe pain."

When the chick grows up, she is put into the cage where she will spend the whole of her life until she is taken out to be killed. The size of the cage varies, but typically she will be squeezed into an area around 30cm x 50 cm (12 inches by 20 inches), along with three or four other chickens.

This gives her around 300 sq. cm or about 48 sq. inches. She can barely move.?Some farmers might argue that the animals are used to this environment, and are not suffering. This is nonsense. Marian Dawkins, a zoologist at Oxford University, showed that chickens will choose a free run to a cage, even if the cage has food in it. They are aware of their predicament and actively avoid it if given a chance.

Not only is her cage far too small, it was designed in complete indifference to her needs, and purely for the convenience of the human operator. For example, it has a wire floor so that her droppings don't need to be removed regularly; however, the wire cuts into her feet. Not cleaning out her droppings saves time - but it also means that the air is heavy with ammonia, which damages her lungs.

The floor is sloped so that her eggs fall down into the chute. This makes it difficult for her to stand comfortably. Because of her extreme confinement, almost all her natural instincts are frustrated. For example, when it is hot she wants to dust-bathe, like other birds. In the cage, she will repeatedly go through the motions, rubbing her belly against the wire floor until she bleeds.

Even the British Ministry of Fisheries and Food (MAFF) accepts that one reason why she will peck out the feathers of her companions is because of the frustration caused by her inability to dust-bathe. Battery hens are typically bald and bleeding from sores.

But perhaps the most important instinct which is frustrated is the need to find a quiet place to build a nest. The ethologist Konrad Lorenz compares this to the human need to defaecate in private: "... it is truly heart-rending to watch how a chicken tries again and again to crawl beneath her fellow cage-mates, to search there in vain for cover."

Marian Dawkins has demonstrated that the instinct to dust bathe and to create a nest can be stronger than the urge to eat. Hens who refused to squeeze through a narrow space to reach food did do so in order to reach material to build a nest or a dusty floor where they could dust bathe.

In her natural environment, a hen would lay about sixty eggs a year. Today, according to MAFF, she produces five times this number. A report commissioned by Compassion in World Farming showed that the combination of low calcium and lack of exercise causes the animals' bones to become brittle due to osteoporosis.

One study showed that 29% of animals arriving at the slaughterhouse had at least one freshly broken bone. Towards the end of their lives, the hens become so exhausted that their production drops. They are therefore starved and kept in the dark in order to force them to moult. Donald Bell, a poultry researcher at the University of California, recommends they be starved for up to two weeks, but the time varies. The ones that survive this shock produce a few more eggs before they are finally turned into chicken soup.

Forced moulting is illegal in the UK, but not in the US. The reason these atrocities continue is that they are still legal. They are legal because agribusiness lobby groups buy influence, both in government and in the media.

Money talks, chickens don't.

Yet even as long ago as 1964, the British government commissioned a scientific study under Professor Roger Bramwell to examine the welfare issues raised by intensive farming.

It concluded unambiguously: "An animal should at least have sufficient freedom of movement to be able without difficulty to turn around, groom itself, get up, lie down and stretch its limbs"

Almost forty years later, very little has been done. Battery hen farming is still legal everywhere in the world apart from Switzerland. The European Union will phase it out in 2012. The United States, inevitably, refuses to even consider the matter, and allows cage sizes that are so small they would be illegal in other countries.