plicity of building these pens following the step-by-step directions set forth herein.
First, consider the great advantages of using dropping trays. 99 per cent of pen odors may be due to unsanitary conditions such as stale urine and the vaporous residue of same. Pens with self-cleaning area feature in floors require only a little longer to build, but save hours of cleaning time. Urination through the self-cleaning area into the droppings tray saves this offensive odor and prevents needless contamination of food. Hamsters like clean pens, so much of the excreta and other waste particles pass into the droppings trays. Trays may be emptied each week or 10 days without disturbing food stores or nests, and favor a pleasant, profitable situation. Laboratories and producers alike are rapidly turning to such self-cleaning advantages. No technician likes to handle animals carrying filth and foul odors; neither are such welcome about the home. Avoid both by proper construction of the pens. Illus. 2 shows a stack of such pen units with self-cleaning floor features, pen supports (P. S.) permitting free use of droppings trays (Drp. Tr.).
18. Pen Habits
Illus. 3 and 4 give details of hamster pen habits. Pens of approximately 71⁄2- to 9-inch widths simulate native quarters, food stores, etc., and are called standard
ILLUSTRATIONS OF HAMSTERS’ PEN HABITS
pens. Pens of 10- to 12-inch widths are oversize and permit must waste of materials, foods, etc. F.P. shows where the caretaker places food. F,F,F,F show where the hamster stores the food. The sloping apron of nesting materials (A) leads up to the nest (N). Caretaker drops nesting materials at F.P. Excelsior, straw or grass may be used. Excelsior is preferred, and the animals make their own nests. Instinctively, the nests are usually made about the same size. In
