Assessing the carbon footprint of egg production from white and brown laying hens under a No-Culling Male Chick system: a Dutch case study

Producing more ethical and animal-welfare friendly eggs is a public demand. This study was carried out to provide more insight into the environmental impacts of no-culling of male chicks (NCMC) in a laying hen (white and brown breeds) production system in the Netherlands. A life cycle assessment was conducted and three phases including i) the rearing and laying periods of parent stocks, ii) the hatchery stage, and iii) the rearing and laying periods of hens, were assessed. Based on the obtained results, the carbon footprint (CF) of market egg equipped with NCMC was 2.31 and 2.74 kg CO 2 eq/kg eggs for white and brown breeds, respectively . Feed production and land use change were the main contributors to the total greenhouse gas (GHG) emissions of parent stocks and hens phases. According to our findings, application of NCMC technique increased GHG emissions at hatchery stage by 98% and 56% for white and brown breeds. However, use of NCMC led to less than 1% higher CF of market eggs at the end of laying period of hens 1%. The higher GHG emissions were due to i) higher energy consumption, ii) higher egg losses, iii) higher errors in the sex determination process, and iv) lower hatchability. This modest rise in emissions showed that more animal friendly and ethical production can be achieved through the implementation of NCMC with minimal environmental trade-offs. Integrating such practices with improved feed techniques may offset the extra emissions while delivering higher sustainability outcome in overall. Comparison of different allocation methods demonstrated that the choice of allocation method influences the estimated effect of implementing the NCMC strategy on the CF of market eggs.