Tuesday, May 6, 2014

Welfare the hot-button issue for poultry

Animal welfare is emerging as the hot-button issue for Ontario’s poultry industry, so it was no surprise that several university students presented their research results to the industry during a meeting organized in Guelph recently by the Ontario Ministry of Agriculture and Food and the Poultry Industry Council.

Teresa Casey-Trott found in her research for a doctoral degree that the aviary housing systems that animal welfare activists prefer actually results in a greater incidence of deformed keel bones in young birds.

She focused on pullets to find out whether the incidence of broken bones in egg-laying hens, when they are reaching the end of their productive lives, can be reduced.

She found that no matter how they are housed, there is a relatively high incidence of broken bones – 18 to 25 per cent of the birds kept in conventional cages, 60 to 85 per cent of those housed in aviaries where they can roam free a fly or climb up to perches.

“No one thing solves the problem” of osteoporosis, she said.

She delved into whether “load-bearing exercise” by pullets might result in a lower incidence of broken keel bones among relatively old laying hens. It does, but when before they begin laying eggs, these exercised birds had a greater incidence of deformed keel bones.

She found that exercise increased three types of bone material – the cortical material that is the strong exterior part, the trabecular, which is softer interior material, and the medullary, which mobilizes calcium.

She is continuing her research to determine how much pressure is needed to break bones of birds raised under different housing systems.

Michelle Hunniford outlined surprising results about the nesting behaviour of egg-laying hens.

Animal welfare activists point to the incidence of eggs laid outside a nest box as a measure of their stress, but Hunniford found that the birds with more space and therefore presumably less stress laid more eggs outside the nests – 33 per cent compared with only seven per cent for birds living in more crowded conditions.

That was with caged birds. Trials with birds in aviaries (an open pen with perches) revealed that they laid fewer eggs in nests than the birds housed in cages.

And so, she concluded, where hens lay their eggs is not a good indicator of animal welfare.

Chantal LeBlanc told how she is conducting research to determine how well birds perform on different degrees of steepness of ladders or slopes to higher levels, such as perches or nesting boxes.
One of the issues is their ability to keep their balance and from suffering injuries.

Madison Kozak told how well four different strains of egg-laying birds adapt to aviary housing systems.

Stephanie LeBlanc is studying how well birds can maintain their balance on a swinging perch. For some trials, she blindfolds the birds. For others, she crowds them with puppet birds on either side.

She’s trying to find out why so many birds injure themselves when they are housed in aviaries.