Timothy hay is the gold standard for adult rabbits, guinea pigs, and chinchillas. It provides the high fiber, low calcium, and low protein balance that these herbivores need for healthy digestion and continuous dental wear. Hay should make up 80 percent or more of their daily diet and must be available at all times.

Timothy hay comes in three cuttings. First cutting is coarser with more seed heads and stems, offering maximum fiber and dental grinding. Second cutting is the most popular balance of leaf and stem, softer but still fibrous. Third cutting is the leafiest and softest, useful for tempting picky eaters but slightly lower in fiber. A mix of first and second cutting is ideal for most pets.

Alfalfa hay is not appropriate for healthy adults due to its high calcium and calorie content, which can lead to bladder sludge, kidney stones, and obesity. However, alfalfa is excellent for young animals under six months, pregnant or nursing mothers, and underweight animals recovering from illness, as the extra nutrition supports growth and recovery.

Orchard grass is a good alternative or supplement to timothy hay. It has a similar nutritional profile but a softer texture and slightly sweeter taste, making it appealing to picky eaters. Meadow hay, oat hay, and botanical hay blends also work well as variety alongside timothy.

When buying hay, look for green color, a fresh grassy smell, and minimal dust. Brown, musty, or damp hay should be discarded, as it may harbor mold that causes respiratory illness. Store hay in a cool, dry place in a breathable container rather than sealed plastic, which traps moisture.

Avoid hay marketed primarily for bedding, as it is often lower quality and too dusty for feeding purposes.