The Rural Voice, 1993-10, Page 27economical in space, be labour
saving in the same way the cages are
and yet let the birds live in a situation
that was closer to their natural
lifestyle.
The aviary is a room with three
horizontal tiers down the middle
where birds can roost, eat or drink.
The outside walls hold group nests
where the hens can go to lay eggs in
seclusion. The floor space between
the centre tiers and the outside walls
is layered with shavings where the
birds can walk, fly and socially
interact.
Systems for
collecting eggs and filling
feed containers are designed
so that the farmer doesn't
have to enter
the aviary.
"I was surprised
we had such good
results on the first
shot", he says of the
design that was first
developed at Guelph.
Usually such new
designs need a period
of gradual improve-
ments, he says. He
read about other
experiments to
redesign housing for
hens before he made
his design. "I tried to
filter it through my
own knowledge and
objectives to design
the thing."
The experiment
has been ongoing
since, because he
wanted to see what
the effect of the
housing was on the
lifespan of animals. "I
the lifespan. Longevity accumulates
all the positive and negative factors
as the animal goes through its life
and reflects it in a very complex way
in one single parameter which is
measurable."
While one part of the flock was
being kept in the free barn system,
their sisters were being kept in a high
quality battery cage system with as
many of the same external conditions
as possible. The diet was the same,
the shape of the room was the same,
the size of the room and the
ventilation, even the person looking
after both groups of hens was the
same.
Production results were very close
between the two systems with the
in the run system. That's natural
because the energy needed for
walking, flying, running and
scratching and litter bathing has to
come from somewhere.
"One of the very pleasant
surprises was that in the free run
system, we didn't have any
meaningful level of aggression,
aggression that would lead to so-
called cannibalism." Cannibalism is a
sign of boredom or frustration, he
says, not of any need of the birds to
feed themselves.
At the beginning of the
experiment none of the birds in either
system had their beaks trimmed but
there were incidents of cannibalism
in the cages so he decided that each
group would have
its beaks trimmed
only if there was
any sign of need.
There was never
any need to trim
the beaks of the
birds in the free
range system.
One of the
moderations to
the free range
system has been
an effort to
combat problems
with egg eating.
The eggs roll
down from the
nests for easy
gathering but the
birds were
spending time in
the nests at night.
Now, the nests
lift out of the way
at night, prevent-
ing the birds from
using them as sleeping quarters. If
birds spend too much time in the
nests the nests aren't as clean.
A
djustments have also been
made to prevent hens
laying eggs on the floor.
Hens like dark corners for
laying so by providing
light in the corners they aren't so apt
to lay on the floor. Having enough
nesting space also reduces the
problem of floor eggs. The incidence
of floor eggs is surprisingly low,
Prof. Hurnik says.
The poultry industry hasn't been
beating a path to his door for the
Professor Hurnik' s aviary at the Arkell Research Station . (Photo by Owen Roberts).
wanted to use
as a measurement mortality and
morbidity. So I kept the birds there
for three consecutive years.
(Normally Canadian poultry farmers
replace their birds every year so they
won't have to moult before they start
laying again. In the U.S. forced
moulting is sometimes used to keep
hens laying for two years, he says.)
My interest was not in forced
moulting, but to see if longevity
would give me some sort of
indication (of the well-being of the
animals). I believe one of the good
signs for quality of life for animals is
battery cage system slightly in the
lead. "In the third year we had much
higher mortality in battery cages than
in our free range system. The
feathering of the birds is much nicer
in the free range system. The birds
were much calmer, more content than
in the cage system.
"Which says perhaps that the
opportunity to have more exercise,
the opportunity to walk, run, fly,
jump, the opportunity to avoid some
aggressive peers, altogether
contributes to the better longevity.
"On the other hand, we had
somewhat higher feed consumption
OCTOBER 1993 23