By Dr Duncan Houston
A full hay rack is only useful if your animal is actually eating from it. For rabbits, guinea pigs and chinchillas, regular hay chewing supports digestion, tooth wear and natural feeding behaviour.
This guide explains how to choose and offer hay, what each species needs alongside it, and when refusing hay deserves veterinary attention. These feeding recommendations are specific to these three herbivores.
Quick Answer
Rabbits, guinea pigs and chinchillas should have good-quality hay available throughout the day and night, with grass hay forming the foundation of most healthy adults' diets. It supplies fibre, encourages prolonged chewing and gives them opportunities to forage. Hay does not replace drinking water or each species' other nutritional needs. A sudden reduction in eating or droppings needs prompt veterinary advice, and complete appetite loss requires an immediate call.
How does hay support digestive health?
These animals extract nutrients from fibrous plants with help from microbes in the hindgut. Guinea pigs are adapted to a diet high in fibre and relatively low in energy. The MSD Veterinary Manual's guinea pig nutrition guidance recommends grass hay as the foundation of an adult diet, supplemented with suitable pellets and produce.
In rabbits, too little fibre and too many carbohydrate-rich foods can contribute to digestive problems. However, gut stasis, where intestinal movement slows, can also follow dental pain, another illness or stress. Adding hay cannot treat an animal that has already stopped eating. See VCA's explanation of rabbit gastrointestinal stasis.
Learn your animal's usual droppings rather than expecting every species to produce identical round pellets. Notice their number, size and consistency, alongside appetite and activity. Hay is dried forage, so fresh drinking water must always be available.
What does hay do for teeth?
Rabbits, guinea pigs and chinchillas have continuously growing cheek teeth as well as incisors. Eating fibrous forage promotes chewing and normal wear. Pellets and chew objects do not remove the need for hay.
Diet is only part of dental health. In guinea pigs, vitamin C deficiency, injury and inherited factors can also contribute to dental problems. A normal-looking pair of front teeth does not rule out painful teeth farther back. Drooling, dropping food or choosing softer foods deserves attention, even if your animal still accepts treats. The MSD Veterinary Manual's guinea pig dental guidance describes these causes and the need for a thorough mouth examination, sometimes with imaging.
How much hay should each species have?
Keep edible hay available continuously and refill before it runs out. Watch each animal eat, particularly in a shared enclosure. A large amount disappearing does not prove that every companion had enough.
| Species | Hay and feeding priorities | Important difference |
|---|---|---|
| Rabbits | Hay and suitable fresh grass should make up most of the diet. A rabbit-sized bundle of hay daily is a useful starting guide, with more available as needed. | Include appropriate leafy greens and a measured amount of rabbit pellets. Introduce diet changes gradually. |
| Guinea pigs | Provide unlimited good-quality grass hay, with suitable fresh foods and guinea pig pellets. | They need a reliable dietary vitamin C supply. Hay alone and rabbit pellets cannot meet their needs. |
| Chinchillas | Make hay the main food, alongside a measured portion of chinchilla pellets. | Follow a chinchilla feeding plan rather than copying a rabbit or guinea pig vegetable menu. |
These priorities follow the RSPCA's feeding guidance for rabbits, guinea pigs and chinchillas. Young, pregnant, nursing, underweight or chronically ill animals need individual advice about the rest of their diet.
Which hay should you choose?
- Grass hay: Timothy, orchard grass and appropriate meadow or oat hay are useful options. Availability varies by region; several suitable varieties can work well.
- Alfalfa, also called lucerne: This legume hay contains more calcium than most grass hays. It can suit certain growth or reproductive feeding plans, but is not the default for every adult. Ask your vet before using it to address an animal's weight loss.
- Quality: Look for dry, clean hay with a fresh grassy smell and little dust. Reject damp, musty or visibly mouldy hay. Natural colour and texture vary between batches, so colour alone is an unreliable quality test.
The RSPCA Australia's hay guidance discusses suitable varieties and the higher calcium content of lucerne. Store your supply somewhere dry and check it before feeding. Offer a new suitable variety alongside familiar hay; a healthy animal does not require constant rotation.
Can hay improve mental wellbeing?
Searching through hay and chewing give animals useful things to do. The RSPCA's rabbit dietary enrichment guidance recommends offering hay in different ways and using part of the daily pellet allowance for foraging.
Try several accessible hay stations or a shallow box containing loose hay. For rabbits, a few normal pellets hidden in hay can encourage searching without adding treats. Keep an easy feeding station available too, so enrichment never makes essential food difficult to reach.
Use containers without sharp edges or openings that could trap a head or limb. Supervise unfamiliar setups and remove materials your animal swallows in chunks. Hay activities complement space to exercise, hiding places, a calm routine and suitable companionship. The RSPCA NSW small-animal welfare advice explains these wider needs for rabbits and guinea pigs. Persistent aggression or fur chewing needs its own assessment.
What if your animal eats less hay?
| What you notice | What it may mean | What to do |
|---|---|---|
| Rejects one new batch but eats familiar hay normally | Preference, poor quality or an awkward feeding setup may explain it. | Offer familiar clean hay, check access and continue watching appetite and droppings. |
| Eats less hay, selects softer foods, drools or loses weight | Dental pain or another illness needs consideration. | Contact your vet today. Do not spend several days trying different brands first. |
| Stops eating, passes very few or no droppings, or becomes painful or weak | Serious digestive disease or another acute illness is possible. | Call a vet immediately for urgent assessment. |
Alongside teeth, a vet may assess hydration, the abdomen, body weight and other sources of pain. Excess pellets, difficulty reaching a rack or competition for food can contribute, but illness must not be dismissed as fussiness. In guinea pigs, MSD's routine care guidance stresses prompt attention to appetite loss, weight loss and abnormal behaviour.
When is this an emergency?
Call an emergency veterinary clinic immediately if your rabbit, guinea pig or chinchilla stops eating, particularly with absent droppings, a swollen abdomen, obvious pain, marked weakness or breathing difficulty. Do not wait overnight to see whether fresh hay solves it.
In rabbits, gut stasis and intestinal obstruction can look similar but need different treatment. MSPCA-Angell's guidance on stasis and obstruction explains why prompt examination matters. Keep hay and water accessible while arranging care, but do not start syringe feeding, gut motility medicines or home remedies unless the treating vet advises them for this episode.
A practical daily hay routine
- Check morning and evening: Observe each animal eating, inspect droppings and confirm that drinking equipment works.
- Keep hay clean: Remove soiled hay promptly and replenish the edible supply. Position it where your animal can reach it comfortably.
- Review the whole diet: Measure pellets and avoid continually topping up bowls. Guinea pigs also need appropriate vitamin C-rich foods and fresh, correctly stored guinea pig pellets.
- Track changes: Record weight regularly on suitable scales and note persistent changes in intake. Arrange routine checks with a vet who treats the species.
- Support normal behaviour: Provide daily exercise and safe places to explore. Introduce a simple new foraging setup gradually while retaining familiar hiding and feeding areas.
Common hay-feeding mistakes
- Assuming a full rack means every animal is eating enough.
- Withholding familiar food to force an animal with a poor appetite to eat hay.
- Expecting hay to correct established dental disease.
- Using alfalfa as a universal solution for weight loss without investigating the cause.
- Feeding lawnmower clippings to rabbits or guinea pigs. Offer suitable uncontaminated grass, introduced gradually, instead.
Frequently asked questions
Can pellets replace hay?
No. These three species need hay as a major part of their diet. A vet may prescribe a modified feeding plan for an animal with dental disease or another medical problem.
Does my guinea pig still need vitamin C if it eats hay?
Yes. Guinea pigs cannot make their own vitamin C. Provide guinea pig-specific pellets and suitable vitamin C-rich vegetables; ask your vet whether supplementation is needed for your animal.
Is timothy hay the only suitable choice?
No. Other appropriate grass hays can work well. Clean hay that your animal readily eats matters more than choosing a particular name.
My rabbit eats treats but refuses hay. Can its teeth still hurt?
Yes. Selective eating can be a sign of dental pain or digestive illness. Contact your vet rather than assuming that accepting treats means everything is normal.
Make hay eating part of your health check
The aim is steady, comfortable eating supported by a suitable overall diet and a stimulating home. Keep hay available, notice what each animal actually eats, and take a change in appetite seriously. Feeding improvements support health, while prompt veterinary assessment addresses problems that hay alone cannot fix.
For more practical small-pet care information, explore ASK A VET™. If your animal stops eating or becomes unwell, contact your veterinary clinic directly for timely care.
The ASK A VET™ Tracker logs live location and activity trends, so a change in routine never goes unnoticed.
Every ASK A VET article is written and reviewed by qualified veterinarians.
