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PRODUCTION
Prior to World War II, most egg production came from farm flocks of less than 400 hens. By the early 1960s, improved technology and the development of sophisticated mechanical equipment were responsible for a shift from small-farm flocks to larger commercial operations.
Currently, there are about 245 egg-production companies with flocks of 75,000 hens or more and these firms represent about 95% of all laying hens in the U.S. Of these 245 firms, 60 have 1 million layers or more and 12 have more than 5 million layers. In 2006, the average number of laying hens in the U.S. was 288 million. These hens produced an estimated 215.8 million cases of eggs, each case containing 30 dozen eggs, or almost 270 eggs per hen per year.
Factors That Influence Egg Production
Genetic pattern of the breed of hen
Maximum production of top-quality eggs starts with a closely controlled breeding program emphasizing favorable genetic factors. The Single-Comb White Leghorn hen dominates today’s egg industry. This breed reaches maturity early, utilizes its feed efficiently, has a relatively small body size, adapts well to different climates and produces a relatively large number of white-shelled eggs, the color preferred by most consumers. Brown-shelled eggs are now available in most markets, but have long been the traditional favorite in the New England region. Commercial brown-egg layers are hens derived from the Rhode Island Red, New Hampshire and Plymouth Rock breeds which predominated in that area of the country.
– See Color, shell
Hen’s age at egg-laying maturity
Although early starters lay more eggs, maturity too early results in many small eggs.
Resistance to disease
Selective breeding is reinforced by good sanitation and vaccination.
Light control
Of primary importance during both the growing and laying periods, controlled, low-intensity light can be used to delay sexual maturity until the bird’s body is big enough to produce larger eggs. Today’s laying hen doesn’t need to depend upon the fickle sun to tell her when laying time has arrived. Intensity and duration of light can be adjusted to regulate production
Temperature
Laying houses maintained between 57 and 79º F (14 and 26º C) are desirable.
Humidity
A relative humidity between 40 and 60% is best.
Replacing or molting the flock
Molting, or loss of feathers, is a natural occurrence common to all birds regardless of species. As the hen ages, egg quality declines and, at about 18 to 20 months of age, molting occurs and egg production ceases. While some flocks are sold for slaughter at this point, replacement is costly. A fairly common practice is to place the flock into a controlled molt. A low-protein diet minimizes stress on the birds. After a rest period of 4 to 8 weeks, the birds start producing again. Egg producers have found that with two periods of controlled molting, one at 14 months and another at 22 months, egg quality is more consistent than with one molt at 18 or 20 months.
The laying house
In today’s egg-laying facilities, temperature, humidity and light are all controlled and the air is kept circulated. The building is well insulated, windowless (to aid in light control) and force-ventilated. Birds are either given the run of the floor area or are housed in cages. Most new construction favors the cage system because of its sanitation and efficiency, but floor operations are also in use.
Feeding and Quality of Feed
Because care and feeding of hens, maintenance, sanitation and egg gathering all take time and money, there is a strong trend toward automation whenever possible.
Automatic feeders, activated by a time clock, move mash through troughs in the floor or past the cages. Birds at floor level drink from troughs; birds in cages may sip from such sophisticated accessories as self-cleaning drinking cups or nipple valves.
Since more is known about the nutritional requirements of the chicken than of any other domestic animal, rations are scientifically balanced to assure layer health along with optimum quality eggs at least cost.
Most poultry rations are of the all-mash type. They might be made of sorghum grains, corn, cottonseed meal or soybean-oil meal, depending on the part of the country in which the ration is produced and which ingredient is most available. The feed is carefully balanced so that the hen gets just the right amounts of protein, fat, carbohydrates, vitamins and minerals. Today’s hen eats a better balanced diet than many people do.
The hen’s ration may contain the same types of additives approved for human food. Antioxidants or mold inhibitors (also used in mayonnaise and bread) are added to maintain the quality of the feed. An additive is not approved for use in poultry feed unless adequate research has been undertaken to determine its pharmacological properties and possible toxicity and to discover any potentially harmful effects on animals.
Federal regulations prohibit the feeding of hormones to any kind of poultry in the U.S. Antibiotics are only rarely used when chickens are ill, at which time they seldom lay eggs. If antibiotics are used, FDA regulations require a withdrawal period for laying hens to ensure eggs are free of antibiotics.
How much a hen eats depends upon the hen’s size, the rate of egg production, temperature in the laying house and the energy level of the feed. In general, about 4 pounds of feed are required to produce a dozen eggs. A Leghorn chicken eats about 1/4 pound of feed per day. Layers of brown-shelled eggs are slightly larger and may require more feed.
The type of feed affects egg quality. Shell strength, for example, is determined by the presence and amounts of vitamin D, calcium and other minerals in the feed. Too little vitamin A can result in blood spots. Yolk color is influenced by yellow-orange plant pigments in the feed. Maximum egg size requires an adequate amount of protein and essential fatty acids.
Handling
The moment an egg is laid, physical and chemical changes begin to conspire against freshness. Warm temperatures encourage those changes, so newly laid eggs must be gathered frequently and refrigerated quickly.
Some eggs are still gathered by hand but, in most production facilities, automated gathering belts do the job. Gathered eggs are moved into refrigerated holding rooms where temperatures are maintained between 40 and 45º F (5 and 7º C). Humidity is relatively high to minimize moisture loss but shouldn’t exceed 80%. About 10% of eggs are oiled as they are gathered.
– See Oiling
Processing and distribution
Some producers sell their eggs nest-run (ungraded) to processing firms which clean, grade, size and carton the eggs and ship them off to retail outlets. Most farms and ranches carry out the entire operation.
– See Egg Products, Egg Products Inspection Act, Grading, Nest-Run Eggs |
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