Sawdust should be avoided because it tends to collect within the external genitalia of males, forming an impaction. Rarely does this impaction interfere with urination, but it may inhibit successful breeding. Guinea pigs seem most comfortable when they are spared exposure to excessive noise, needless excitement and confusion, and other stresses. Sudden environmental changes should also be prevented. Guinea pigs have 2 types of reactions when startled by a loud noise or sudden movement or when placed in a strange environment.
Panic involves erratic running and leaping, often accompanied by shrill squealing.
Groups of guinea pigs may stampede in a circle, often trampling the younger residents within the enclosure. A panic reaction scatters bedding and food, fouling the food and water containers. Rectangular enclosures containing barriers also reduce the tendency to stampede and circle. Food and water must be readily available at all times. Commercially available pelleted chows provide all of the essential nutrients, as long as the pellets are fresh and wholesome when offered.