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. In the major egg producing states, flocks of 100,000 laying hens are not unusual and some flocks number more than one million. Each of the 235 million laying birds in the U.S. produces from 250-300 eggs a year.
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.
Of primary importance both during the growing and laying periods is controlled, low-intensity light that 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.
Since more is known about the nutritional requirements of the chicken than of any other domestic animal, it is not surprising that rations are scientifically balanced to assure layer health along with optimum quality eggs at least cost.
Laying houses are maintained between 57-79°F (14-26°C) with a relative humidity between 40-60%. The building is well insulated, windowless (to aid light control) and force-ventilated. Birds are either given the run of the floor area or are housed in cages.
Most poultry rations are of the all-mash type. They are made of sorghum grains, corn, cottonseed meal or soybean oil meal depending upon 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! In general, about four pounds of feed are required to produce a dozen eggs.
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 18-20 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. After a rest period of 4-8 weeks, the birds start producing again.
Poultrymen have found that with two periods of controlled molting, one at 14 months of age and another at 22 months, egg quality is more consistent than with one molt at 18-20 months.
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.