Agriculture Reference
In-Depth Information
Figure
7.7.
Penkin ducks in the United States.
Ducks are less widely distributed than chickens, being mostly raised in North and
South America, Eurasia, and Australia. As shown in Figure 7.9, the largest populations
are found in China, Hungary, Indonesia, and Vietnam. They are almost absent in sub-
Saharan Africa. Because ducks are aquatic birds, they are most commonly raised near
ponds, though open water is not necessary for their production.
Geese (shown in Fig. 7.10) are the largest bird commonly raised by humans. They
tend to be raised in the cooler climates, though they can survive tropical conditions.
Figure 7.11 shows the leading producer countries are China, Egypt, Romania, and
Madagascar.
Modern chickens are mostly flightless, due to their long history of domestication.
Chickens are grouped by classes related to their geographic area of development. They
are raised for both eggs and meat. Often chickens are kept for egg production, but when
this declines, they are sacrificed for meat.
Ducks are closely related to their wild relatives, sometimes having colorations
similar to wild species. Ducks are less prolific egg layers than chickens, so they are gen-
erally raised for meat purposes in the United States. In China and the Philippines, eggs
are the most valuable product. Ducks are generally considered to be less susceptible to
diseases than chickens. In some Asian rice-producing countries they are raised as part
of an integrated rice - carp - duck production system.
Geese are multipurpose farm birds. Their large size and rapid growth make them
a preferred meat source in some countries. They are guard animals, being territorial
and quite noisy when strangers enter and are useful for weeding certain crops.
They are also a source of feathers for insulated jackets and bedcovers as well as
meat and eggs.
7.4.1 Biology
Major characteristics that distinguish chickens from other birds are the presence of a
comb on the top of the head and wattles under the chin. These secondary sex
