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.
