Kaytee Timothy Hay for Rabbits is a natural product with no preservatives or additives, and because timothy hay is lower in calcium, it may decrease the likelihood of urinary tract problems. Timothy hay is a natural product with no preservatives or additives. Because timothy hay is lower in calcium, it may decrease the risk of urinary tract problems. For rabbits, guinea pigs, and other small animals.. Natural Sun-Cured Timothy Hay.: Size: 48 OUNCE