Agriculture Reference
In-Depth Information
Building shelter for animals is expensive, so a farmer will
want to keep as many hogs under one roof as possible, but
not so many that the stress of the crowd is detrimental. In
experiments, animal scientists have placed groups of hogs at
different stocking densities (different square meters per pig)
and measured cortisol levels of each group, thereby allowing
one to determine a density that keeps both animal stress and
farmers' costs low.
Another way of inferring an animal's mental state is to sim-
ply let the animal reveal its preferences by presenting it with
choices. These choice experiments even teach animals to pay
a “price” to receive something; instead of paying with money,
the animals pay by performing a physical action. The more
times that action must be performed, the higher the price it
pays. So not only do we measure whether livestock prefers
one thing or another, but also the maximum price they will
pay for each (i.e., a measure of their motivation to obtain a
resource). For example, it is known that hens truly desire nests
for laying eggs because they are willing to squeeze through
a very small hole to reach one. Even if you raise the price by
making the hole smaller, they squeeze through whenever it
is physically possible. Hogs want both to eat and to social-
ize with other animals; we know this because they will press
a lever multiple times for both. They value food more than
socialization, though, because they will press a lever more
times for food.
Scientists study these animal preferences using experi-
ments and mathematical models, the same models econo-
mists use to capture human preferences. Some economists
have gone so far as to measure “total happiness” and “total
suffering” by humans
and
animals in one utilitarian function,
thereby achieving what Jeremy Bentham and Peter Singer
have long advocated: taking animal feelings into account just
as one accounts for human feelings. So, like dog owners, the
livestock industry takes animal feelings seriously—just in a
more technical way.
