An adjustable cylindrical cage is described for use in metabolism studies with male pigs, particularly those below 50–60 pounds live weight. In the experience of the author, several months' trial has indicated that the central funnel arrangement for urine collection is a practical one, highly efficient in permitting separation and collection of excreta. It allows some freedom of movement. The usual preliminary period allows sufficient time for adjusting the size of the cage to the animal. Details of construction and illustrations of the cages in use are included.