Capable personnel shall be employed for the adequate care and feeding of the animals. In small, as well as in extensive animal facilities, one individual shall be in complete charge of, and therefore, responsible for, the entire operation of the unit. Selection of animal caretakers shall be made with care. Nonprofessional personnel shall be chosen for their dependability and their liking for animals. The training should include a knowledge of the means of transmission of disease and an understanding of the precautions necessary to prevent this. Caretakers should be trained in recognizing early symptoms of the common diseases of the animals under their care.