Stichting Hen & Co

Which egg do you pick? A life cycle assessment (LCA) comparison.

The LCA and the Egg

As a conscious consumer, the supermarket presents a lot of difficult choices. Do you pass over the products in plastic packaging and go with paper packaging? What about a biological product or a product with a certain certification?

Take the egg shelves. Do you choose free-range eggs, organic eggs, eggs with a better life quality mark (one, two or three stars?). These options all say something about the way the hens live and are fed, but this does not directly say anything about the environmental impact. A life cycle assessment (LCA) provides insight into where the environmental impact lies.

  1. The LCA and the Egg
  2. Quick scan environmental impact with LCA
  3. Where are the hotspots
  4. How can the environmental impact be reduced?
  5. Small-scale: is it possible to be suststainable?

Quick scan environmental impact with LCA

By using an LCA approach, we take the entire life cycle of an egg into account. The CO2 footprint of a kilogram of eggs varies from approximately 2 to 4 kilograms of CO2 per kilogram of product. This variation is due to a number of factors; such as the difference in the animal feed used, but also in the way in which the chickens are reared. For example, organic eggs have higher CO2 emissions than free-range eggs [1].

At first this may sound contradictory. The feed of organic chickens often comes from the region, while the feed for other chickens often consists of soy (from South America). In addition, when growing the feed of organic chickens, no artificial fertilizers and synthetic pesticides are used [2]. However, the production of this feed is less efficient than for non-organic animal feed; crops fail more often or grow less quickly due to the absence of pesticides and fertilizers [3].

There are many different factors that are taken into account in an LCA when determining the environmental impact of chicken eggs. In this blog we therefore investigate where the hotspots are located within the chain, and how these can be reduced

Where are the hotspots?

An LCA is a systems approach, in which every step in the supply chain is taken into account. One of the factors in which the breeding methods differ from each other is the energy consumption. In general, the more chickens are kept in a stable, the less (thermal) energy needs to be used. However, this difference in energy consumption is dwarfed by the factor that contributes most to CO2 emissions; the feed.

The CO2 emissions of both broiler and laying hens are largely determined by the environmental impact of the administered feed. A chicken eats about two to three kilos of feed per kilo of eggs [4]. These chickens are often fed a mix of soy, wheat and maize, the emissions of which can contribute up to 90% of the total carbon footprint [5]. In addition, the feed conversion is important. The feed conversion for organic chickens is much higher than for other chickens. This means that an organic chicken has to eat more to achieve the same production (chicken meat or chicken eggs).

Een LCA van ei

Land use

Another important factor, which is linked to the feed, is the CO2 impact due to land use change. Soy comes mainly from South America, where a large part of the production is still accompanied by the destruction of tropical rainforests. Despite the lower production efficiency, organic chicken feed has less impact on land use because less soy is used.

However, there is great methodological uncertainty about the accuracy with which the land use impact can be quantified in an LCA. This factor is therefore not included in many studies that calculate the CO2 emissions of chicken eggs. Blonk Consultants allocates an additional 1.6 kilos of CO2 emissions for land use change, but also indicates that this contains a great deal of uncertainty [6].


After the feed, manure is the largest contributor to the total CO2 emissions. In addition to CO2, chicken manure also contains a part of CH4 (methane) and N2O (laughing gas). One kilogram of methane equals approximately 25 kilograms of CO2 emissions, and one kilogram of nitrous oxide is equivalent to 298 kilograms of CO2 emissions! 

Blonk Consultants has calculated that the manure storage and processing of an organic laying hen emits more CO2 than for free-range laying hens. This is mainly due to the higher protein content in the administered feed, which causes more methane and nitrous oxide to be released [5].

Chicken egg sustainable

How can the environmental impact be reduced?

The company Kipster (named the most sustainable company in the Netherlands in 2020) is one of the companies that is actively working on improving animal welfare and reducing CO2 emissions. For example, the laying hens receive a mix of mainly residual flows, supplemented with a small amount of ‘high-quality’ feed. This ensures that the CO2 emissions of the feed are reduced by approximately 50 percent. Despite these residual flows, the feed still contributes 77% to the company’s total CO2 emissions [7].

Nevertheless, Kipster managed to reduce the impact of its eggs to 1.3 kilos of CO2 per kilo of product. Taking animal welfare more into account does not necessarily have to be at the expense of the CO2 footprint. Curious about how your company can get a better grip on your environmental impact? We are happy to help you out!

Stichting Hen & Co

Small-scale: Is it possible to be ‘sustainable’?

Kipster proves that reducing the environmental impact does not have to come at the expense of animal welfare. By using local residual flows, no soy needs to be obtained from South America, which saves CO2 emissions and does not result in extra land use.

Large-scale production is of course more efficient than small-scale production. In practice, however, this does not necessarily mean that the small-scale production of chicken eggs entails a higher CO2 footprint. The advantage of keeping production on a small scale is that local residual flows can be used, which is a bottleneck for large-scale production. This means that small-scale production can not only be better for the chickens, but also for the climate.

At Hen & Co they offer an unique experience in which the chicken and the egg are central. In their projects they support small-scale chicken farming at home in combination with your own vegetable garden. With this you can become (partly) self-sustainable.

[1] Blonk consultants & ABN Amro. (2011). Duurzaamheid in eieren en kippenvlees. Via

[2] Milieucentraal. (n.d.). Eieren. Via

[3] Mommers, J. (2015). Factcheck: ‘Kippen in de wei zijn slecht voor het milieu’. Via

[4] Dekker, S. E. M., De Boer, I. J., Vermeij, I., Aarnink, A. J., & Koerkamp, P. G. (2011). Ecological and economic evaluation of Dutch egg production systems. Livestock Science, 139(1-2), 109-121.

[5] Blonk Consultants & ABN AMRO. (2018).

[6] Blonk Consultants. (2019). De cijfers op een rijtje. Via

[7] Kipster. (2020). Jaarverslag 2020. Via: