In long-lasting experiments the application of Cd resulted in a decreased state of health (nephritis) of hens. Feed consumption, weight gain and egg production were reduced. Egg shell quality was not changed under practical Cd-concentrations. Studies of the ultrastructure of egg shells of animals fed with Cd did not yield any hints of damages. The protein-profiles of egg shells revealed an additional component under Cd-application. 17 references, 2 figures, 2 tables.