All over the world, 7.9 billion laying hens, most of which are kept in cages, contribute to commercial egg production. In the EU in 2022, 39.7% of hens were farmed in enriched (also called furnished) cages, whereas the remaining 60.3% of hens was kept in alternative and cage-free housing systems, i.e. barns (including foor with single tier and foor with multi-tiers aviaries in conventional farms) (37.8%) and free range (15.5%) and organic systems (7.0%) as extensive productions (European Commission, 2024; Council Directive 1999/74/EC; Commission Regulation 889/2008; Kollenda et al., 2020). Enriched cages, intended to provide additional space and resources for satisfying behavioral needs of hens, have a relatively low risk for diseases and parasitism under controlled conditions, besides high economic effciency (Lay et al., 2011; Mench et al., 2011; Campbell et al., 2019). Nevertheless, the European Resolution P9_TA(2021)0295, answering the European Citizens’ Initiative ’End the Cage Age,’ asks for banning any cage system for farmed animals in the EU.