Agriculture Reference
In-Depth Information
Figure
7.10.
Geese in the United States.
characteristics are more prominent in the male but also are present in the female.
The genus name Gallus is derived from the Latin name for comb. They are covered
by feathers with some hairs on the body. The hairs are normally singed off during pro-
cessing. The two legs are covered with scales. Chickens do not have teeth. Grinding is
done in the gizzard by muscles and small pebbles they pick up from the ground. Adult
chickens weigh from 450 g (Dutch) to 4.5 kg (Jersey Giant).
6
Egg size varies with the
weight of the hen and come in colors from white to brown and even blue. A caged
chicken raised under ideal conditions will produce 250 to 300 eggs each year. Under
less than ideal conditions only 30 to 60 eggs per year can be expected.
7.4.2 Chickens
Chickens are believed to be descended from the red jungle fowl (Gallus bankiva)of
Southeast Asia. There are indications that chickens were domesticated as early as
3200
BC
in India, while records show chickens in China and Egypt starting in
1400
BC
. These showed chickens being used for cockfighting rather than for food,
but it is unlikely the hens and their eggs were wasted. Starting in 1849, poultry exhibi-
tions became popular in the United States. This resulted in many breeds and varieties
being preserved and new ones being developed. There are about 60 breeds of chickens
based on body shape, number of toes, and color. The variety of chicken within a breed is
further distinguished by minor variations on coloration and comb. A still more detailed
distinction can be made by strain. Commercial strains exist that have been developed by
companies for specific desirable meat or egg characteristics.
Where are your chickens?
There are approximately two chickens for every human being in the world.
7.4.3 Ducks
Domestic ducks are descended from wild ducks, and some breeds still bear the mark-
ings of their wild relatives. Ducks are more adapted to free-range production than
chickens. They feed on snails and insects in rice paddies during the day and return
