Timothy hay is often regarded as the finest hay for guinea pigs because of its high fiber content and low protein levels. It is minimal in calories and fat, making it suitable for adult guinea pigs. Alfalfa or clover hay can be given to the diet of young guinea pigs, as well as pregnant or nursing females, to supplement protein and calcium in moderation. Other safe options include: Orchard hay Oat hay Meadow hay Always ensure the hay is fresh and free from mold or dust. Consult with a veterinarian for personalized advice tailored to your guinea pig’s specific needs.