The classic Stack with a calming, herbal twist.ÿ Oxbow?s Harvest Stacks ? Western Timothy with Chamomile features all-natural Western Timothy Hay in an innovative, enriching format.ÿ The addition of chamomile makes this product impossible for rabbits, guinea pigs, chinchillas, and other small herbivores to resist.ÿ Feed Harvest Stacks as a primary hay source or supplement with loose hay to encourage enrichment. ÿHarvest Stacks make a great feeding option when traveling or anytime storage space is limited.