Why Hay Must Be 80% of Your Rabbit's Diet

If there is one rule every rabbit owner must know, it is this: hay is not optional. Grass hay should make up approximately 80% of your rabbit’s daily diet, and it should be available in unlimited quantities, 24 hours a day. This isn’t a guideline — it’s a welfare essential backed by every major veterinary and rabbit welfare authority in the world.

Why Rabbits Need Unlimited Hay

Rabbits are hindgut fermenters, which means the bulk of their digestion happens in the cecum — a large, fermentation chamber at the junction of the small and large intestine. This system is perfectly designed for a high-fibre diet of grasses, but it is extremely sensitive to disruption.

Hay provides the indigestible fibre that drives the physical contractions of the gut — called peristalsis. Without adequate fibre, the gut slows and can stop entirely. This condition, known as gastrointestinal stasis (GI stasis), is the leading cause of death in pet rabbits. A rabbit that goes more than 4–6 hours without eating can develop life-threatening stasis within 12–24 hours.

Beyond gut motility, hay performs another critical function: dental wear. Rabbit teeth grow continuously throughout their life — incisors at roughly 2–3mm per week. The abrasive, lateral grinding action required to chew long-strand hay is what naturally wears down both incisors and back molars. Without this daily grinding, teeth overgrow, causing painful spurs, abscesses, and eventually the inability to eat.

“The single most important change an owner can make to improve their rabbit’s health is to ensure unlimited, high-quality grass hay is available at all times.” — House Rabbit Society

The Best Types of Hay for Rabbits

Not all hay is equal. Here’s a breakdown of the most commonly available types:

Timothy Hay (the gold standard)

Timothy hay (Phleum pratense) is widely recommended as the best everyday hay for adult rabbits. It has an ideal fibre-to-protein ratio (roughly 32% fibre, 8–10% protein) and a texture that promotes excellent dental wear. Look for second-cut timothy, which is softer and leafier — most rabbits prefer it to first-cut, which is coarser.

Orchard Grass (Cocksfoot)

An excellent alternative or supplement to timothy. Orchard grass hay is sweet-smelling and highly palatable, making it a good choice for fussy rabbits or to encourage hay-eating in those transitioning from a poor diet. Nutritionally comparable to timothy.

Meadow Hay

A mix of various grass species found in natural meadows. Meadow hay provides excellent variety and enrichment — foraging through the mixed stems, flowers, and seed heads is great mental stimulation. Quality varies by brand, so source from a reputable supplier.

Oat Hay

Higher in protein and carbohydrates than timothy. Safe to offer in small amounts as a treat or variety supplement, but should not be the primary hay due to the higher calorie content.

Alfalfa Hay — Adults vs. Juveniles

Alfalfa hay is NOT suitable for healthy adult rabbits as a primary hay. It is very high in calcium and protein, which can cause urinary sludge and kidney strain in adult rabbits. However, it is the correct choice for rabbits under 7 months of age, nursing mothers, and underweight or ill rabbits who need additional calories. Once a rabbit reaches adulthood, transition to grass hay over 2–3 weeks.

Signs Your Rabbit Isn’t Getting Enough Hay

Watch for these warning signs that indicate insufficient hay consumption:

• Fewer or smaller droppings — healthy rabbits produce 200–300 small round droppings per day; a reduction is serious
• Soft cecotropes not being eaten — excess cecotropes sticking to the fur around the bottom
• Dental problems — drooling, dropping food, reduced appetite, weight loss
• Obesity — rabbits filling up on pellets instead of hay become overweight
• GI stasis episodes — hunched posture, teeth grinding, no appetite

How to Encourage Hay Eating

Some rabbits, particularly those raised on a poor diet, need encouragement to eat adequate amounts of hay. Try these strategies:

1. Hay rack next to or above the litter tray — rabbits naturally eat while toileting, so positioning hay near the litter box dramatically increases consumption
2. Offer variety — rotate between timothy, orchard grass, and meadow hay to prevent boredom
3. Reduce pellets — pellets are calorie-dense and filling; reducing the ration incentivises hay eating
4. Hide treats in the hay — bury a few herb leaves or dried flower petals to encourage foraging
5. Freshness matters — hay should smell sweet and green, not musty or dusty

How Much Hay is Enough?

The quantity should be unlimited — your rabbit should always have access to a fresh pile of hay. As a rough guide, a ball of hay roughly the size of your rabbit’s body per day is the minimum. In reality, most healthy rabbits eat significantly more than this.

The RabbitCare App Can Help

Tracking your rabbit’s daily hay intake and monitoring their droppings is one of the most important health habits a rabbit owner can develop. The RabbitCare App (available free on Android) includes daily care checklists, health tracking, and reminder notifications to top up hay, check the litter tray, and log any changes in droppings. Download it today to build a consistent care routine for your rabbit.

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References & Sources

1. House Rabbit Society (HRS) — “Diet: Hay” — rabbit.org
2. Rabbit Welfare Association & Fund (RWAF) — “Feeding Rabbits” — rabbitwelfare.co.uk
3. PDSA — “What do rabbits eat?” — pdsa.org.uk
4. Varga M. (2014) — Textbook of Rabbit Medicine, 2nd edition, Elsevier
5. Harcourt-Brown, F. (2002) — Textbook of Rabbit Medicine, Butterworth-Heinemann
6. Prebble, J.L. & Meredith, A.L. (2014) — “Food and water intake and selective feeding in rabbits on four feeding regimes” — Journal of Animal Physiology and Animal Nutrition