Impacts associated with egg production include the environmental effects of feed production, nutrient (waste) management and transportation, as well as the ethics of hen treatment and the nutrition and health of egg consumers.
Commercially raised hens are fed specially formulated feed that consists of corn, cottonseed, soybean meal, and/or sorghum. Sometimes animal by-products (bone meal, animal fat, etc.) are also added to increase protein content, but have been linked to animal disease outbreaks and the risk of transmission of bacteria, such as salmonella.
While animal manure can be a valuable fertilizer and soil conditioner, if excessively applied or improperly handled, it can generate odorous air emissions, nutrient (particularly nitrogen and phosphorus) runoff to water bodies and volatilized ammonia (which can contribute to eutrophication of surface water). These problems have been magnified as poultry and livestock production has become more concentrated. And since eggs from laying hen houses contain traces of manure on the shell, many states require that the water used to wash the eggs be collected and processed accordingly – usually stored in lagoon systems for application to croplands via irrigation systems.
Maryland Egg Quality Assurance Program (MEQAP) eggs, though not guaranteed to be free of Salmonella enteritidis (SE), come from producers and/or processors who have implemented management and monitoring practices most likely to prevent SE contamination. The Maryland Department of Agriculture (MDA) provides oversight and technical advice to this voluntary program. http://mda.maryland.gov/foodfeedquality/Pages/egg_quality_assurance.aspx
Organic eggs are produced by hens given feed grown without most conventional pesticides, fungicides, herbicides, or commercial fertilizers. The use of growth hormones and antibiotics is also prohibited, though growth hormones are not used in U.S. commercial egg production (all eggs are hormone-free, whether or not they are labeled as such) and antibiotic use (to treat sick birds) is not routine industry practice (hens typically stop laying eggs when ill). www.ams.usda.gov/nop
Vegetarian eggs are produced by hens whose feed is free of animal by-products.
Free-range eggs come from hens that are either raised outdoors or have access to the outdoors. Due to seasonal conditions, however, few hens are actually raised outdoors and access to outdoors can vary greatly between producers.
Cage-free eggs come from hens living in indoor floor facilities (usually the floor of a barn or poultry house) and do not necessarily have access to the outdoors.
United Egg Producers (UEP) certified eggs comply with the UEP guidelines developed by an independent scientific advisory committee made up of scientists from government agencies, academia, and the US Humane Association to assure that eggs come from hens living in humane conditions with attention to living environment, health care, and treatment. Egg producers participating in the UEP Certified program must comply with minimum space requirements per bird and are audited annually by a third party organization. www.uepcertified.com
Omega-3 enriched eggs are the result of adding flax, marine algae, or fish oils to feed, boosting omega-3 fatty acid content in egg yolks. Higher vitamin E content is an additional benefit of omega-3 enriched eggs.
Animal Welfare Approved eggs come from independent family farms compliant with standards for health and flock management, handling, transport and slaughter. Animal Welfare Approved hens are vegetarian-fed, not subject to forced molting, and able to range and forage.http://animalwelfareapproved.org/standards/layinghens-2014/
Shell Eggs Specification
301 West Preston Street, Baltimore, MD 21201