"A review of risk factors for Salmonella in laying hens revealed that overall evidence points to a lower occurrence in non-cage compared to cage systems. [...] There is conclusive evidence that an increased stocking density, larger farms and stress result in increased occurrence, persistence and spread of Salmonella in laying hen flocks". EFSA Panel on Biological Hazards (EFSA BIOHAZ Panel), Koutsoumanis, K., Allende, A., Alvarez‐Ordóñez, A., Bolton, D., Bover‐Cid, S.,... & Lindqvist, R. (2019). Salmonella control in poultry flocks and its public health impact. Efsa Journal, 17(2), e05596.
