Enriched cages seem to be a suitable substitute for conventional cages from 2011 and from alternative systems, it would be an aviary. These housing systems provide more space to move for hens and the natural intuitive behaviour compared to conventional cages. Moreover, in terms of the economy, hens achieve higher egg production and better feed conversion here. In addition, eggs from these housing systems have higher weight but also a higher level of quality of egg content and eggshell. Lower microbial contamination of eggshell and lower probability of subsequent contamination of egg content is their other advantage. Cuticle, shell and shell membranes form a barrier which protects the eggs against penetration of microorganisms, but the risk of penetration increases with time. Therefore, it should prevent the hens from contamination of eggs with their faeces. This is basically solved in hens kept in cages.