Feeding BAY Vi 7533 to hens

BAY Vi7533 (2-chloro-N-[[[4-(trifluoromethoxy)phenyl] amino] carbonyl] benzamide) was fed to White Leghorn and Vedette Mini-broiler breeder hens at concentrations ranging from 0 to 25 ppm in the ration. Concentrations of 15 and 25 ppm resulted in greater than 95% mortality of house flies, Musca domestica L., seeded as larvae into the droppings. Concentration of 25 ppm reduced egg production in the White Leghorn but not in the Vedette Mini-broiler hens. At each concentration (except 5 ppm for Vedette Mini-broilers) residues of the compound were detected in the eggs. These residues, however, had no adverse effects on fertility or hatchability of the eggs.