Breeding Can Prevent Cannibalism in Hens

by 5m Editor
26 April 2010, at 10:05am

US - Cannibalism can be a problem in non-cage housing systems but Purdue University and a breeding company have bred a line of less aggressive hens that can be kept in more extensive systems without being beak-trimmed.


KTVB reports that researchers say decades of breeding to make the white leghorn hens that lay most of the nation's eggs more productive have also boosted the birds' territorial instincts, making them prone to pecking attacks so fierce they're often called cannibalism.

Scientists and egg producers warn that deadly skirmishes that start with feather-plucking and turn into bloody frenzies when a bird's pecking breaks a flockmate's skin will increase if those same aggressive hens are moved from small cages with five to 10 birds to open pens that can hold dozens.

Animal rights groups want those pens to replace the small battery cages they call cruel because hens are so confined they cannot spread their wings.

Seven states have passed laws that will eventually ban or limit different types of livestock cages. Two of those states – California and Michigan – have passed laws that will eventually ban battery cages for chickens, as has the European Union.


The easy-going egg-layers Dr Muir has dubbed 'Kinder Gentler Birds' do not need their beaks trimmed and blunted, another industry practice deplored by animal rights groups but which is intended to prevent pecking deaths, according to KTVB.

Breeders working over several decades chose the most productive birds to reproduce, resulting in white leghorns that each year can lay 300 to 320 of the large bright-white eggs most popular with Americans. Dr Muir said that approach unintentionally produced birds that also have a heightened self-preservation instinct and desire to literally be at the top of the pecking order.

"If you have a lot of birds that want to be top bird there's going to be fighting," Dr Muir said. "If you leave their beaks intact it's a bloodbath. They will literally kill each other. It's kind of a dominance thing. They just peck each other to death."

About five per cent of hens on intensive farms die each year from injury and disease. To reduce fights, they are kept in dim lighting in cages where each bird has an average 67 square inches of space, or two-thirds of a sheet of notebook paper.

The Humane Society of the United States maintains such conditions cause hens needless suffering and increase their agitation by limiting their ability to walk around and preventing them from acting on natural urges to peck, nest and perch.

"It really is difficult to imagine a more restricted, miserable existence," said Paul Shapiro, senior director of the Humane Society's campaign against factory farming.

Gene Gregory, president of United Egg Producers, a trade group that represents farms that produce about 90 per cent of the nation's eggs, said there would be more pecking deaths in open cages and egg prices would go up because more workers would be needed to manage the birds.

Mr Shapiro agrees that costs would rise but disputes the claim that moving hens from battery cages to open pens would cause more deaths. He said proper management can result in no difference in death rates and adds that pens could reduce attacks by allowing hens to perform natural behaviors such as pecking the ground.

He acknowledges that breeding gentler chickens would be a plus if it could eliminate the practice of break trimming.

Ian Duncan, a professor emeritus of animal welfare at University of Guelph in Canada has also advocated for an end to keeping hens in battery cages, but he said commercial white leghorns would have a higher rate of cannibalism in pens.

Cannibalism is a learned behaviour, passed from one territorial hen to another, he said, and while he views battery cages as a grim existence, the fact is those cages limit contact between birds and make pecking easier to manage.

Professor Duncan said: "It seems counter-intuitive – you would think that it might be worse in a battery cage – but it's not, it's worse if you keep birds in big groups."

He said Dr Muir's work holds the promise of making commercial hens better suited for a more spacious lifestyle and less prone to clashes.

Dr Muir said it is hard to compare his and his colleagues' birds with the more aggressive ones that have become the poultry industry standard, but he believes their hens would live longer and lay more eggs because they waste less energy fighting.

KTVB reports that Hendrix Genetics, a Dutch company that breeds the layers that produce about half the world's eggs, has begun using Dr Muir's technique, breeding birds chosen for their personality as well as their ability to lay eggs.

The company had already been working on a breeding technique aimed at producing more robust animals with lower death rates, said Gerard Albers, director of Hendrix Genetics' BV Research and Technology Centre. But he said Dr Muir's ideas gave it a boost as the European Union moves closer to its 2012 deadline for abolishing battery cages.

The company's work is moving faster now, he said, and the first of its gentler birds will be available in three years.