Hay doesn’t always get the love it deserves. People often see it as simple bedding or boring “filler,” but for rabbits and guinea pigs, hay is truly the heart of a healthy diet. It’s packed with the fiber their bodies depend on. Fiber isn’t just part of their diet, it is their diet. Every chew of hay helps maintain a balanced gut, healthy teeth, and a happy, stress-free pet. Fiber is why they need hay all day, every day!
In this guide, we’ll explore:
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Why fiber is a big deal for rabbits and guinea pigs
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How hay keeps digestion humming and prevents tummy troubles
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Why hay works like nature’s toothbrush
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How hay helps your pet feel calm, confident, and enriched
- Which hays are best and how to choose the perfect one for your furry friend
So let’s hop (or wheek) right in and begin with where every healthy rabbit and guinea pig diet starts: with fiber.
Fiber’s Role in Rabbit and Guinea Pig Digestion
In the wild, cavies (i.e., wild guinea pigs) graze on low-calorie, high-fiber grasses in the Andes Mountains. Rabbits around the globe mostly eat grass as well.
Hay is simply a dried form of these grasses.
While hay does not have a lot of fat or protein, it has one very important nutritional component: fiber. When it comes to rabbits and guinea pigs, fiber is king. In fact, hay should make up at least 80% of these small pets’ diets and they should have access to hay all day, every day.
Hay contains two types of fiber, insoluble and soluble, both of which keep these small herbivores’ systems working properly.
- Insoluble fiber is made up of the long, tough strands found in hay that move through your pet’s digestive tract mostly unchanged. This type of fiber adds bulk and helps the digestive system push food through, which is extremely important for preventing GI stasis.
- Soluble Fiber comes from hay’s finer particles and softer plant components. This is the type of fiber that gut microbes love. It’s fermented by billions of bacteria, which turn hay into cecotropes.
If you’ve ever wondered why rabbits and guinea pigs eat their “poop,” they actually don’t. They are eating cecotropes, a special nutrient-rich type of dropping and they often eat it directly from their anus. Yes, it might seem a little gross to us, but for rabbits and guinea pigs, it’s not only natural, it’s where a ton of their nutrition comes from.
How Rabbits and Guinea Pigs Digest Food
Rabbits and guinea pigs don’t have strong enough digestive enzymes to break down grass and hay on their own. Instead, they rely on helpful microbes in their gut to do the work for them. These microbes need fermentable food to thrive.
Small herbivores are hindgut fermenters, which means they ferment their food in a special pouch at the end of their small intestine, called the cecum. This pouch is packed with billions of bacteria and other microorganisms that work hard to turn these fermentable fibers into essential nutrients.
Fermentation allows small herbivores to survive on low-calorie, high-fiber plants that many other animals can’t digest.
Here’s how it works:
- Food quickly goes through their stomach and small intestine, then into the cecum.
- The cecum’s muscular contractions sort soluble and insoluble fiber.
- Insoluble fiber quickly passes on to the large intestine, physically stimulating movement throughout the digestive system.
- Soluble fiber is broken down (fermented) in the cecum by billions of microbes.
- The cecum releases nutrient-rich, fermented fiber into the colon as cecotropes, which are expelled separately from fecal pellets.
The digestive system works properly only when it is continuously moving, and fiber is what keeps it going.
What Happens if a Rabbit or Guinea Pig’s Gut Slows Down?
A tummy ache is serious when it comes to your bunny or cavy. When your small pet’s gut slows down, whether from a lack of hay, stress, changes in diet, or other causes, it sets off a dangerous chain reaction. This can quickly lead to GI stasis, a potentially life-threatening condition.
Here’s how it happens:
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Food stops moving the way it should.
Rabbits and guinea pigs rely on constant gut movement, and fiber is what keeps everything flowing. When there isn’t enough long-stem fiber to push things along or enough fine particles to ferment properly, food can start to linger in the stomach, intestines, or cecum instead of moving steadily through. -
The cecum’s microbes fall out of balance.
If food sits too long, the healthy bacteria in the cecum begin to decline, while gas-producing bacteria take over. This shift (dysbiosis) makes the digestive system even more unstable. -
Gas builds up, causing painful bloating.
This gas stretches the gut and becomes very uncomfortable. Rabbits and cavies can’t vomit, so the pressure just keeps increasing. -
Pain reduces appetite, which slows the gut even more.
At this point, you might notice your pet hunching, grinding their teeth, acting lethargic, or looking bloated. It’s a red flag that the slowdown is getting worse. -
Your rabbit or guinea pig stops eating.
Once appetite drops off completely, gut movement comes to a halt, creating more gas and more pain. -
Cecotropes turn mushy, become irregular, or stop appearing.
Because the cecum can’t ferment properly, cecotropes lose their normal shape or disappear altogether. This means your pet isn’t getting the vital nutrients cecotropes normally provide. -
Dehydration sets in.
Food sitting in the stomach starts to dry out and turn into thick, doughlike masses that are hard (and painful) to pass. -
Full-blown GI stasis develops.
At this stage, the digestive system has essentially shut down. GI stasis progresses quickly and can become life-threatening within hours.
Signs of GI stasis include:
- No appetite
- No poop (or very small, dry pellets)
- Cold ears
- Lethargy
- Rapid breathing or weakness
- Belly discomfort
- Sitting in a pressed-down “pain posture”
- Tooth grinding (a sign of pain)
If you notice any of these signs, contact your veterinarian right away.
Fiber and Your Pet’s Dental Health
Fiber plays a key role not only in digestion but also in your rabbit or guinea pig’s dental health. Hay serves as their natural dental care, helping prevent painful and sometimes even life-threatening dental disease, while also reducing the risk of GI stasis.
Unlike cats and dogs, rabbits and guinea pigs aren’t born with a fixed set of teeth. Instead, their teeth grow continuously throughout their lives, which means they must grind them down every day to keep them at a healthy length.
Hay acts like nature’s toothbrush. Its long, fibrous strands require hours of side-to-side chewing, which naturally polishes and wears down the teeth, helping prevent sharp points, spurs, or dangerous overgrowth.
Pellets and leafy greens, on the other hand, disappear in minutes and barely challenge the teeth. They simply cannot replace the steady, prolonged grinding that hay provides.
Signs of Dental Problems
Dental issues in rabbits and guinea pigs aren’t always easy to see, but many of the symptoms are. It's important to keep an eye out for:
- Drooling
- Wet chin or chest
- Weight loss
- Difficulty picking up food
- Selective eating (choosing soft foods only)
- Dropping food while chewing
- Reduced hay intake
- Abnormal cecotropes
- Smaller or fewer fecal pellets
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Scratching at the mouth
Fiber and Behavior: How Hay Helps Keep Small Pets Happy
In the wild, rabbits and cavies graze 6 to 12 hours a day.
Family rabbits and guinea pigs still have that natural instinct. Their mental well-being is closely tied to grazing, foraging, and chewing. A diet rich in high-quality hay provides natural enrichment throughout the day, keeping their mouths active and their minds engaged.
For added enrichment, you can offer hay in fun, creative ways, such as:
- Hay tunnels
- Hay-filled dig boxes
- Mixed hays with herbs and flowers
- Scatter-feeding hay around the enclosure
- Hide-and-seek hay toys
- Hay stuffed into paper bags, toilet tubes, or baskets
When rabbits and guinea pigs get the chance to hunt, dig, and forage for hay, they’re expressing natural behaviors that help make them calmer, happier, and more confident.
Your small pets will thank you for it, and you’ll thank yourself. Having plenty of fiber to chew makes them less likely to chew on the wrong things.
Which Type of Hay is Best?
Hay, like grass, comes in a variety of types and forms. Let’s look at some of the most common types.
Timothy Hay
Timothy hay is the most popular type of hay for small pets, offering the ideal balance of fiber, texture, and nutrition. It’s similar to what rabbits and cavies eat in the wild.
Timothy hay is harvested three times each season, which is why it’s available in three different cuttings (1st, 2nd, and 3rd). Each of the three cuttings is slightly different nutritionally, giving small pet parents options based on their pet’s age and health needs.
- 1st cut timothy hay has the most fiber, and contains more stems and even some flower heads. It is especially helpful if your rabbit or guinea pig needs strong digestive or dental support.
- 2nd Cut timothy hay is the balanced, “middle ground” option, offering an ideal mix of fiber and leafiness. It contains enough stems to support healthy digestion and dental wear, while its higher leaf content makes it more appealing to many pets. This balance makes 2nd cut timothy hay our most popular cut and is an excellent choice for many rabbits and guinea pigs.
- 3rd Cut timothy hay is the softest and leafiest option. Its higher leaf content and lower stem count make it richer in fat and protein, which can benefit older pets, picky eaters, or those needing help maintaining weight or appetite. However, because it contains fewer coarse stems, it is generally less effective for dental wear and may not provide enough fiber for pets with higher digestive needs.
Another important factor is that timothy hay is naturally low in calcium. Rabbits and guinea pigs do not require large amounts of calcium. They need only moderate calcium levels to support bone health and normal body functions. What makes them unique is how they process calcium:
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Rabbits and guinea pigs absorb almost all the calcium they eat, regardless of how much their body actually needs.
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Any excess calcium must be removed through the kidneys and passed out in the urine.
- Because of this, diets that are too high in calcium can cause urinary problems such as sludge, crystals, or bladder stones.
While young bunnies and guinea pigs benefit from additional calcium during growth, most healthy adults thrive on low-calcium grass hays such as timothy, orchard, or meadow.
Orchard Hay
Another popular option is orchard hay, which is similar in fiber and calcium content to timothy hay, but a little softer and more aromatic.
Rabbits and guinea pigs often enjoy orchard hay, and it can be an effective way to encourage them to eat more hay, especially if they are picky, older, or ill. Because it is softer, orchard hay is not as effective for grinding down teeth, but it can be mixed with timothy hay to add aroma and variety.
Since orchard hay is not grown as widely as timothy hay, it is usually a bit more expensive. However, it can be well worth the investment for selective eaters or for pets recovering from digestive slowdowns. Orchard hay is also a helpful alternative for small pet parents with timothy allergies, as it is less likely to trigger sneezing or irritation.
Alfalfa Hay
Another hay option is alfalfa hay, typically recommended for small herbivores. Unlike grass hays such as timothy and orchard, alfalfa is a legume hay, which naturally makes it higher in protein, calories, and calcium. These elevated levels can contribute to urinary issues and unwanted weight gain in healthy adult rabbits and guinea pigs, so alfalfa is generally not recommended for long-term adult diets.
However, alfalfa does have an important role. Young, growing rabbits and guinea pigs (as well as pregnant or nursing mothers) can benefit from its extra nutrients and higher energy content.
Balancing Your Small Pet’s Diet
A balanced diet keeps your rabbit or guinea pig healthy, happy, and active. While the exact proportions may vary slightly based on age or health needs, the ideal daily diet generally looks like this:
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80–85% Unlimited Hay
Again, it’s the foundation of their diet. Hay provides the essential long-strand fiber that helps keep digestion moving, teeth worn down, and your small pet happy.
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10% Vegetables
Fresh vegetables add valuable variety and flavor to your companion’s diet. Be sure to offer only produce that’s recommended and safe for rabbits or guinea pigs. Introduce new items gradually, in order to help prevent digestive upset.
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5% High Quality Pellets
Food pellets are a supplement, meant to support their main nutritional intake from hay. *Guinea pigs require vitamin C in their pellets.
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<5% Limited Fruits & Treats
Fruits should be considered occasional treats for rabbits and guinea pigs. Like fruit, healthy treats are best saved for bonding, enrichment, and training moments. Think of them as an occasional dessert, not dinner.
Finally, fresh, clean water should be available at all times. Water and fiber work together to keep digestion moving smoothly and to prevent dehydration, which can contribute to gut slowdown or urinary issues.
A well-balanced diet starts with hay, and choosing a fresh, high-quality variety ensures your rabbit or guinea pig gets the nutrition and enrichment they depend on.
Sourced from trusted family farms, Small Pet Select hay is hand-packed fresh to preserve its aroma and nutrient content, supporting natural foraging, healthy chewing, and strong gut motility.
With consistent quality in every box, you can feel confident your rabbit or guinea pig is getting the very best fiber-rich hay every single day.
FAQs
Can rabbits eat hay cubes instead of loose hay?
Hay cubes can be a helpful supplement, but they should not replace fresh hay for rabbits or guinea pigs. Because cubes are made from compressed, shorter pieces of hay, they don’t provide the long-strand fiber needed for proper digestion. Hay cubes can be great for enrichment and variety, but fresh loose hay is essential for the natural foraging behaviors and continuous chewing these small pets rely on to stay healthy.
How should I store hay so it stays fresh?
Hay stays freshest and crunchiest when stored in a cool, dry, well-ventilated space, such as the Small Pet Select box it arrives in. Avoid sealing hay in airtight containers like plastic bins since hay needs airflow to prevent moisture buildup and mold.
Be sure to store hay away from direct sunlight, heat sources, and damp areas like basements.
Which type of hay is best for allergies?
For those suffering from hay allergies, Orchard Hay is a great option. It provides nearly the same nutritional benefits as timothy hay and small pets love it!
How much hay should my small pet eat per day?
A healthy rabbit or guinea pig should always have fresh, fragrant hay within reach. This means keeping hay available 24/7 and refilling it whenever it starts to run low. Hay should make up around 80%-85% of your rabbit or guinea pig’s daily diet.
If your small pet doesn’t seem to be eating enough hay, you might try offering different hay varieties such as adding orchard hay to your timothy hay mix. You can also add hay-related enrichment activities like hiding it in tubes or boxes to make hay munching more fun.
Be sure to also provide constant access to fresh water, which helps them digest hay.
Be sure to limit fresh leafy greens and veggies to around 10% of their diet and pellets to 5%. Fruits and other treats should only be given occasionally.
Is alfalfa hay ever okay for adult rabbits or guinea pigs?
Alfalfa hay is higher in protein and calcium than grass hays like timothy or orchard, which can increase the risk of bladder issues and excess calorie intake in adult rabbits and guinea pigs. For this reason, grass hay should be the primary daily hay for healthy adults. Alfalfa can be appropriate for young, growing, or nursing animals, but it should not be routinely fed to healthy adults.
