Chicken Egg Production
Eggs are produced by hens (female chickens) on farms. Hens begin laying eggs when they are 4-6 months old. A good laying hen will produce 6-7 eggs per week for the first 1-2 years of her life. Chickens are domestic fowl, as are turkeys, ducks, and geese. All species of poultry lay eggs. Chicken eggs are most commonly consumed in the United States.
Eggs come in various shell colors, although there is no nutritional difference between different colored eggs. The shell color depends upon the breed of chicken. Eggs can be white, tan, brown, or even a light shade of green. Chickens can be raised on a large or small scale. A few chickens can easily be raised in a backyard to provide eggs for a family. Eggs that are purchased from a store likely came from a farm. Chickens live in houses called coops. They eat a special feed that includes grains, such as ground up corn and wheat.
Eggs that are produced for the purpose of eating will never develop into a chick because the eggs are not fertilized by a rooster and they are never incubated (kept warm). On a farm, eggs are collected each day. The eggs go through a processing plant where they are washed, checked for cracks and abnormalities, sized, graded, and then packaged. The contents of an egg can be seen by a method called candling (holding it up to a light). If an egg has an abnormal shape or appearance, it is discarded and the remaining eggs are packaged into cartons. The eggs leave the processing plant in refrigerated trucks which deliver them to retail grocery stores to be sold to consumers.
Egg Grading
Eggs are graded into three classifications according to the United States Department of Agriculture (USDA) grading system—AA, A, and B. The grade of an egg is determined by the interior and exterior quality of the egg. Grade AA eggs have thick, firm whites and the yolks are free from any defects. Their shells are clean, smooth, and oval in shape. Grade A eggs have a slightly lower interior quality. Grade B eggs may have slight stains and be irregular in shape. Grade B eggs are not sold in supermarkets, but are used in powdered or liquid egg products. There is no nutritional difference between the different grades.
Egg Sizes
Egg size is determined by the average weight per dozen. Jumbo eggs are 30 oz. per dozen, extra large are 27 oz., large are 24 oz., medium are 21 oz., small eggs are 18 oz. per dozen. The age, breed, and weight of the hen as well as environmental factors influence the size of an egg. As a hen ages, the size of her eggs increase. Underweight birds lay smaller eggs. Stress, heat, overcrowding, and poor nutrition can also result in smaller eggs. Eggs are weighed by electronic scales and packaged by size based on weight.
Egg Nutrition
The 2020-2025 Dietary Guidelines for Americans includes eggs in all three of its healthy eating patterns. The nutrients in eggs support brain development in early life and health across the lifespan.1 Eggs are a good source of protein and are a good or excellent source of eight essential nutrients including choline, an under-consumed nutrient the Dietary Guidelines recommend to support brain health.
Eggs are one of the few natural food sources of vitamin D, which along with calcium is critical for building strong bones. Egg yolks contain lutein and zeaxanthin, carotenoids that can support eye health as you age. The science on dietary cholesterol and eggs continues to grow and demonstrates that eggs are an important part of healthy dietary patterns across the lifespan.2
Numerous research studies show that students who eat breakfast—either at school or at home—have better academic performance and behavior.3 When children eat better, they learn better. A well-balanced breakfast, rich in protein, whole grains, fruits/vegetables and low-fat/fat-free milk gives children the energy they need to let learn and stay active. The protein in eggs, in combination with a well-balanced breakfast, can help keep children satisfied and fueled. Breakfast options that include eggs present opportunities to include other nutrient-dense foods encouraged by the 2020-2025 Dietary Guidelines for Americans, such as vegetables and whole grains.
Egg consumption by American children and adolescents is associated with intake of several nutrients, including higher protein, polyunsaturated, monounsaturated and total fat, alpha-linolenic acid, docosahexaenoic acid, choline, lutein + zeaxanthin, vitamin D, potassium, phosphorus, and selenium.4
Though eggs can be prepared in various ways for breakfast, they are also important and commonly used in other foods. Eggs help bind ingredients together, act as a leavening agent, and help to thicken soups and sauces.
