The Rural Voice, 1992-02, Page 23function" — the motions are how the
animal gets rid of built-up tension
from general over -stimulation. The
differences are significant — is that
hyena pacing because it is bored, or is
it pacing because hordes of people
stare at it day after day? Two differ-
ent problems, with two different solu-
tions.
Dantzer feels that there is little
evidence for either scenario, and pro-
poses another interpretation of stereo-
typic behaviours. He believes that in
the face of certain types of stress, a
process is begun in which normal be-
haviours gradually disappear, coupled
with the simultaneous emergence of a
smaller range of repetitive behaviours.
This is the result of actual damage to
normal nervous pathways: he believes
that "the occurrence of stereotypes
reflects a cut-off of higher nervous
functions." In the absence of "con-
scious" behavioural censorship, a
range of unconscious behaviours
found in the lower brain stem emerge.
Dantzer says such animals "would be
unable to feel any emotion while they
are engaged in their stereotypes, but
(this) provides no excuse for the
design and use of facilities that result
in such abnormal behaviour."
This last interpretation may
explain what happens to an animal
when it develops a stereotypic beha-
viour, but it does little to tell us in
what way the animal's housing should
be changed to avoid the disorder. So
more recently, researchers have been
concentrating on determining more
precisely which behaviours an animal
must be allowed to perform in order
that it not suffer in ways that create
stereotypic behaviour.
On the surface, it may not seem
logical that the deprivation of a "lux-
ury" behaviour like dust bathing for
chickens can lead to intense behav-
ioural abnormalities, but a closer look
at the issue shows this is not so. Ac-
cording to Marian Stamp Dawkins of
the Animal Behaviour Research
Group at the University of Oxford,
"subjective feelings, including the un-
pleasant ones of `suffering,' have a
biological function." An animal that
suffers from hunger is motivated to go
and search for food. Dawkins feels
that in nature, an activity such as dust
bathing can also have a direct survi-
val function, because it keeps the
bird's feathers in good condition,
enabling it to escape from predators.
Therefore, the bird is motivated to
perform dust bathing not as a luxury,
but for survival, so the deprivation of
this activity is perceived by the bird
as life-threatening. Being unable to
do anything about this, the bird first
becomes frustrated, then helpless, and
such stress finds its expression in
abnormal activity.
This difference in perception
between what humans feel an
animal needs, and what the
animal feels it needs, can be
large indeed.
It's also not predictable. This is
underscored in an experiment carried
out by R. H. Bradshaw and N. E.
Bubier of the Animal Behaviour Re-
search Group at the University of Ox-
ford. Testing the effect of space on
how often chickens flapped their
wings, they found that the birds pre-
ferred a space two times as large as
they physically needed. The authors
say it is an unexpected finding that
the chickens' "perception of space
needed is larger than the wingspan."
These inconsistencies in need
create many problems for the scien-
tists who have been asked to measure
and determine farm animal welfare.
In order to find out accurately what
the animal needs for adequate wel-
fare, the animal must be asked — our
guesses are not good enough. But ex-
actly how does one go about asking
an animal what it cannot live with-
out?
The simplest way is to observe
which activities an animal chooses to
perform when left to its own devices.
This can be done in a number of
ways. One is to watch free -ranging
farm animals to see what they do with
their spare time. This provides a lot
of information about which behav-
iours are important to the animals,
and which are not. So in the case of
free-range pigs, piglets spend much
more time exploring their environ-
ment than well-fed sows do. These
adults will choose to lie still for long
periods of time, indicating that piglets
need more overall stimulation than
adult pigs. Such information may not
be very precise, but it at least gives
some general parameters to consider
when designing housing for pigs of
different ages.
Another way of testing what an
animal prefers is to present it with
two different environments and see
which one it chooses to live in. This
can lead to some surprises. Early
research found that chickens prefer-
red to stand on hexagonal wire mesh
instead of a coarser rectangular mesh.
But many of the findings confirm the
intuitive conclusion that intensive
livestock rearing procedures arc not
very good for the animals. Chickens
kept in small cages for three months
avoid such cages when given a larger
one to go into.
There are some criticisms of these
general approaches, however. Re-
viewing the scientific assessment of
animal welfare, D. M. Broom says
that the criticisms arc twofold. In the
first place, "the animal may not
choose what is best for it." This
manifests itself in behaviours such as
over -eating. The second criticism is
that "the action required in order to
make the choice in an experiment is
often very easy. As a result, there is
little indication of the importance of
the choice to the individual."
The latter criticism is the most
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