Egg Industry

The egg industry is the sector of agriculture that produces eggs for human consumption, overwhelmingly from domestic chickens. Commercial egg production takes place on a very large scale, with flocks numbering in the tens or hundreds of thousands of birds on many farms. Vegans avoid eggs, and practices within the industry are frequently cited in arguments for ethical veganism.

Laying hens

Modern laying hens are the result of intensive selective breeding. Whereas their wild ancestor, the red junglefowl, lays a small number of eggs per year in breeding seasons, commercial laying breeds typically produce around 300 eggs per year. This high rate of production places considerable demands on the hen’s body, particularly on calcium reserves, and has been associated with health problems including:

• Osteoporosis and bone fractures, particularly fractures of the keel bone.
• Reproductive disorders, such as inflammation of the oviduct.
• Feather loss and injuries from pecking, especially at high stocking densities.

Laying hens are usually slaughtered when their production declines, commonly at around 18 months to two years of age, although chickens can live considerably longer.

Housing systems

Egg production systems are commonly divided into the following categories:

Legal definitions and requirements vary between countries. Welfare organisations generally regard cage-free and free-range systems as offering more freedom of movement, but note that they can still involve high stocking densities and problems such as pecking and disease.

Male chicks

Because male chicks of laying breeds do not lay eggs and do not grow quickly enough to be profitable for meat, they have traditionally been killed shortly after hatching, most commonly by gassing or maceration. This practice affects billions of chicks worldwide each year and occurs regardless of whether the hens are later kept in cages, barns or free-range systems.

In response, technologies for in-ovo sexing, which determine the sex of an embryo inside the egg so that male eggs can be removed before hatching, have been developed and commercialised. Germany banned the killing of male chicks from 2022, and France introduced a similar ban in 2023. Vegans note that in-ovo sexing does not address other aspects of egg production.

Other practices

Additional practices that have attracted criticism include:

1. Beak trimming, the partial removal of the beak to reduce injurious pecking.
2. Forced moulting, historically used in some countries, in which feed was withdrawn to induce a new laying cycle; this has been restricted or abandoned in many places.
3. Transport and slaughter of “spent” hens, which may suffer injuries due to fragile bones.

Environmental and public health aspects

Eggs generally have a lower environmental footprint per gram of protein than beef or lamb, but a higher footprint than most plant protein sources such as legumes and tofu, according to the 2018 meta-analysis by Poore and Nemecek published in Science. Large poultry operations have also been associated with outbreaks of avian influenza, leading to the culling of millions of birds in several countries in recent years. See environmental impact of animal agriculture.

Alternatives

Eggs perform several roles in cooking, including binding, leavening and emulsifying. Plant-based alternatives include:

• aquafaba, the liquid from cooked chickpeas, used for meringues and mousses
• ground flaxseed or chia seed mixed with water, used as binders in vegan baking
• silken tofu and chickpea flour for scrambles and omelettes
• commercial egg replacers and mung-bean-based liquid egg products

See egg substitutes for more detail.

See also

• Dairy Industry
• Factory Farming
• Animal Sanctuaries