chickens

chickens

Hen and Rooster are, respectively, the female and the male of the species Gallus gallus domesticus of galliforms and fasianídeas birds. Juveniles are called chickens or Galetos, and the chicks, chicks, chicks (European Portuguese) or chicks (Brazilian Portuguese).

These birds have small beak, fleshy crest, scaly legs and short, wide wings. The chicken has a huge importance for man, the most widespread and abundant domestic animal on the planet and one of the cheapest sources of protein. In addition to its meat, chickens provide eggs. The feathers also have industrial uses. According to 2003 data, there are about 24000 million chickens in the world. In some countries of modern Africa, 90% of households keep chickens. Chickens are omnivorous birds, with preference for seeds and small invertebrates.

Chickens are an important food source for centuries. The first references to domesticated chickens appear in Corinthian pottery dating from the seventh century BC The introduction of this bird as a pet probably arose in Asia, where it is native the red junglefowl (Gallus gallus).

Humans began domesticating chickens of Indian origin in order to use them in fighting cocks in Asia, Africa and Europe, with little attention given to the production of meat or eggs. Recent genetic studies point to multiple maternal origins in Southeast, East and South Asia, and with the clade found in the Americas, Europe, Middle East and Africa originating in the Indian subcontinent. Although the Romans had developed the first distinctive breed of chickens, the old records show the presence of Asian wild birds in China from 1400 B.C ..

From India the domesticated fowl made its way to the Persian satrapy of Lydia in western Asia Minor; poultry were imported into Greece in the fifth century BC Chickens were known in Egypt since the 18th Dynasty, as the "bird that gives birth every day" having come to Egypt from the land between Syria and Shinar, Babylonia, according to the annals of Thutmose III. From Ancient Greece, chickens spread across Europe and the Polynesian navigators took these animals in their colonization of travel by the Pacific Ocean, including Easter Island. The ancestral proximity to the man allowed the crossing for the creation of various breeds, adapted to different needs.

Flight

Domestic chickens do not usually fly, as the wild can fly short distances. In some cases, the chickens still have their wings clipped to prevent leakage

reproduction

When the chicken is born, all the eggs that will be generated throughout its life are already stored on your ovary, but in microscopic size, however, is only in adulthood that they are ready for ovulation.

The birds breed, usually during the spring and early summer. Chicken does not depend on rooster to produce eggs, but the participation of the rooster is essential for fertilization to occur them. The male is the sperm provider they need to merge with the female egg to occur fertilization.

The most common mating ritual is a rooster perform a kind of dance around the chicken, dragging their wings while walking in a circle around the female. Usually the chicken is withdrawn, then the rooster chases and ride it to start the process of insemination. Another ritual involves rooster intelligence. It attracts the chickens to where there is food, clucking in a high pitch and then leaves it to feed first. While they are busy, the cock suddenly is on the female chose to mate.

Roosters do not have a reproductive organ that resembles the penis. Instead, they have an opening called the cloaca. The cock position your next cloaca to the chicken cloaca and deposit his sperm inside. The rooster sperm are very hardy and can survive several days inside the chicken. During this period, she is fertile and eggs can cause chicks.

Within the ovary, the egg yolk in development is bound by membranes called follicles, which are broken when the mature egg is reached. The yolk or the egg falls in the infundibulum (process called ovulation), where it remains for approximately 20 minutes and fertilization occurs if there is sperm. In the infundibulum is formed Chalaza, thick membrane that protects the yolk and will result in the clear.

Then, the oocyte (unfertilised) or fertilized egg, continues its way to the magnum, which is surrounded by the light at a time, approximately two to three hours. Leaving the magnum, the egg goes to the isthmus, last region of the reproductive tract before the uterus.

In the isthmus are secreted and the keratinous fiber membranes composing the membrane testacea found in the egg shell. This process adds proteins and small amount of water to the albumen.

The uterus is the addition of large amounts of water. Inside, the egg gets a viscous mass, secreted by the lining of the organ. This mass is the basis for the shell formation and solidifies after being filled with calcium crystals and carbon. This is the longest stage of the process. The egg in the uterus is about 20 hours. In utero also happens to formation of the egg cuticle.

After this period the egg passes through the vagina. To prevent the egg contact residues of feces and urine present in the cloaca, the vagina juts out at the time of posture.

The eggs hatch chickens because embryos require heat to develop.

To check if the egg has been fertilized, it uses the candling. From the eighth day of incubation, it is possible to observe the existence of embryo using a light beam. In infertile eggs no passage of light, while the fertile forms a shadow that indicates the presence of the embryo.