An animal cage is described suitable for automated use in a vivarium. The cage comprises a study animal; bedding; pathogens; a wireless, a sterilizable scale comprising a sterile case comprising a flexible, penetrated membrane; and a penetrating fastener penetrating the membrane. The comprises four internal volume areas with respect to pathogen content: (1) volume between the membrane and a weighing platform, free of bedding; (2) a sterile volume inside the scale case below the membrane; (3) a vertical channel fluidly connecting the inside of the cage with the first volume; and (4) the inside of the cage outside of the above three volumes. These four volumes are sterilely isolated from air outside the cage. Electronics in the scale communicate wirelessly, through the cage, to cage-associated electronics outside the cage, using narrow beam communications free of device-ID specific protocol. The scale may be disassembled, sterilized in a fluid, re-assembled, and re-used in a different cage.
