Science supports caged birds

Kitchener, Ontario - Bans on caging hens are gaining momentum across North America, most recently in approval of a referendum in California calling for a ban by 2012.

But scientific research indicates caged birds are healthier, cleaner and easier to manage.

That means those arguing for the bans are speculating that the hens urges to nest, feather dust and enjoy more space more than offset the pain and suffering from increased bacterial and viral infections, pecking and cannibalism, foot and leg problems and more parasites.

Dr. Tina Widowski of the University of Guelph said all of the research results in the nine years since cage bans began in Europe confirm these comparisons.

So the question becomes the degree of weighting the public and politicians assign to these factors, Widowski said.

Research continues, mainly into methods to measure stresses on the birds that seem to be frustrated by being caged. She said the key stressor seems to be their inability to nest. They seem to be less upset by inability to dust bathe.

There us very little evidence that hens experience frustration when deprived of dust bathing in substrate such as sand, she said. They continue to claw as if theyre dust bathing when theyre standing on wire mesh.

Dust bathing also appears to be an activity that can be switched on with certain stimulations, such as copying other birds that are dust bathing, she said.

The urge to nest is much stronger. They will squeeze through narrow gaps, push open weighted doors and pass through cages occupied by unfamiliar and dominant hens in order to gain access to a nest box, Widowski said.

She said the most complete report on the issues is from the Laywell project which is on the internet at http://en.scientificcommons.org/23366292 .

Dr. Gaylene Fasenko of the University of Alberta talked about studies for the hatching egg industry. She said attention has focused on the hens, so her research team is taking a look at the role of roosters in improving fertility and embryo and hatching survival.

They are also examining the metabolic rate of embryos as a measure of quality eg. are the strains with the fastest growth rates also ones with the highest level of embryonic metabolism? and the influence of rooster and hen ages on productivity.

They have found that poults hatched with a scab covering the navel dont perform as well, and they have delved into that to find that their intestines have lesser development of the villi that capture nutrients.

They speculate that the scab is evidence of infection in the yolk sac and they plan to take a closer look at that. They have also found that the poults with a scab leave more unused yolk behind at hatching.

Dr. Max Hincke of the University of Ottawa told how hes taking a close look at egg shell membranes to identify medicinal compounds that could be harvested. This would make the egg shells from egg-breaking stations more valuable.

Bruce Rathgebar of the federal agriculture department at Truro, Nova Scotia outlined rather disappointing results feeding dried and ground apple peelings to broilers. Their performance was not improved and overall it was difficult to determine if there was a health benefit he said.

He thought there would be, based on the antioxidants in the peels and research indicating that eating apples reduces heart disease.

Michael Czarick III of the University of Georgia talked about barn ventilation, saying that the positioning of air inlets and their capacity is far more important than the placement of exhaust fans.

He advised farmers to avoid systems that pull air through the attic. It should be pulled from side vents.