Phases of the Poultry IndustryThere are three phases of the poultry production industry. One phase is breeding flocks. Once birds reach the age of sexual maturity, they are moved to the laying house. Eggs are collected from breeder farms, taken to a hatchery and stored from zero to ten days prior to being set in an incubator. Hatchlings are processed then transported to commercial grow-out facilities. Another phase is laying hens. A hen begins laying eggs at approximately 18 weeks old. By the end of her first year, she may have produced up to 200 eggs. The third phase is the meat-bird production. The whole house is heated and brooder rings are placed around each brooder unit. When the birds arrive, they are placed into the rings and introduced to the waterers and feed. Broilers are brooded in a portion of the house until a certain age before being given access to the entire barn. Some farms will separate the male and female birds.
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Digestive System |
The digestive system of poultry begins at the mouth. The major functions of the mouth are picking up the food particles and directing the food into the esophagus. The esophagus connects the mouth region to the crop. The crop is a large dilation of the esophagus located just prior to where the esophagus enters the thoracic cavity. The crop provides the capacity to hold food before further digestion begins. Inside the thoracic cavity, the esophagus becomes the proventriculus, often called the glandular stomach. The gizzard, or muscular stomach, is located immediately after the proventriculus. It has a flattened, rounded shape with a layer of tendinous tissue covering the surface. The gizzard almost always contains quantities of hard objects, such as gravel, that aids in the disintegration of food. This is the primary function of the gizzard. The small intestine begins at the exit from the gizzard. The small intestine is the site where much of the digestion and absorption of food occurs. It also produces a number of enzymes involved in the digestion process. The large intestine is sometimes referred to as the colon and the rectum. The large intestine ends in the front part of the cloaca. The cloaca is a tubular cavity opening to the exterior of the body and is common to the digestive and urogenital tract. Fowls do not tend to eat meals on about 15 minute intervals through the daylight hours and during darkness. They tend to eat larger portions at first light and in the late evening. The rate of movement of the food through the digestive system with a meal of normal food takes approximately four hours to pass through in the case of young stock, eight hours in the case of laying hens, and 12 hours for broody hens. Intact, hard grains take longer to digest than the cracked grain and, quite often, some whole grain will pass through unchanged.
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Reproductive System |
The male reproductive organs in the fowl consists of two testes, each with a deferent duct that leads from the testes to the cloaca. Fowls do not have a penis such as is found in other animals. Within the testes are twisted tubes called seminiferous tubules where sperm is produced. The sperm carry half of the total chromosomes required to produce an embryo. The other half is provided by the mother. On average, one cubic millimeter of semen contains three to five million sperm. The testes also produce hormones called androgens that influence the development of secondary sex characteristics, such as comb growth and condition , male behavior, and mating. The deferent duct transports the sperm from the testes where they are formed to the cloaca. The deferent duct enters a small pimple-like structure in the cloaca. This structure equates to the mammalian penis. The female reproductive system in the fowl consists of the ovary and the oviduct. The ovary consists of a mass of yellowish, rounded objects called follicles, each containing a yolk. The normal yolk size in the egg can be up to 40 millimeters in diameter. It takes approximately 10 days for a yolk to develop to the normal size found in eggs, and during this time it is contained in the follicle. The follicle acts as a sack supplying it with the nutrients required for its growth. An area, called the stigma, is where the follicle splits to release the yolk into the oviduct. The function of the oviduct is to produce the albumen, shell membranes, and the shell around the yolk to complete the egg. The oviduct consists of five sections. The infundibulum is located adjacent to the ovary and collects the yolk after its release from the follicle and directs it into the oviduct. Fertilization of the ovum by the male sperm occurs here. The magnum is approximately 40 centimeters long and secretes more than 40% of the albumen. The isthmus is about 12 centimeters in length and secretes some albumen and the shell membranes. The uterus is also about 12 centimeters in length and secretes about 40% of the albumen and the egg's shell. Lastly, the vagina secretes the egg's outer cuticle and pigment. The female reproductive system also produces hormones that aid in the control of body functions. These include androgen, estrogen, and progesterone. Androgen causes comb growth and condition, and has a function in the formation of albumen. Estrogen causes the growth of the female plumage, mating, nesting behavior, and oviduct development together with the nutrient supply to the ovary/oviduct for egg formation. Progesterone is involved in the production of albumen and the carriage of the message to the pituitary gland to release luteinizing hormone (LH). The presence of LH in the blood stream causes the follicle that contains the mature yolk to split along the stigma, thus releasing it into the oviduct.
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