The Best Hay Replacement For Guinea Pigs (A Helpful Guide)

Hay is a food that is important to guinea pigs. But if you can’t get the hay, or are allergic to it, what should you feed them? What is the best hay replacement for piggies?

On the whole, fresh grass is the best choice to temporarily replace hay. Guinea pigs can forage for this in the backyard, replicating natural behaviors, or grass can grown in trays inside. It is important to be selective about the type of grass you use for your guinea pig’s diet, and to introduce it slowly.

a picture of a guinea pig lounging in hay

In this blog post we will discuss the ins and outs of provinding grass as an alternative to hay and examine how to let guinea pigs safely forage grass outdoors,

How To Replace Hay With Grass

best hay replacement for guinea pigs
Grass is usually a good temporary substitute for hay.

If you’ve run out of hay, the best option is to turn to fresh grass. This will be able to keep your furry friends fed until you can get some replacement hay.

This will offer similar nutritional quality and most piggies will enjoy it.

Fresh grass is great for guinea pigs, but can’t be provided year-round in most environments.

The next best thing – hay – provides enough nutrients to keep their movement and digestive system strong and is easier to store and obtain.

So, if you want to use grass as a hay replacement, only do so when you know that you’ll have an ample amount to provide your piggies.

Related Posts

Give the Right Amount of Grass

It’s important to make sure that you’re giving your little friend the right amount of grass. This is one of the core parts of their diet.

Because of this, 75 to 80% of the food they eat should be natural fiber, like hay and grass. This will keep their digestive system working properly and encourage good digestive health. They hay also helps them grind down their teeth, which is a must for your piggie’s dental health. 

Often, this means that you will need to give your piggies a pile of grass that is the same size as their bodies. This should be enough to last them for one day. But, be prepared to add more grass or to change the pile if it becomes dirty or moist.

Choosing the Right Grass To Replace Hay

best hay replacement for guinea pigs
Be careful where you get the grass for your piggies. Either grow it yourself or make sure you have an untreated section of your yard for your little friends to enjoy.

Providing grass isn’t always as easy as a visit to the backyard. Not only do you need to provide unlimited amounts of hay, but there are a few things that you need to check before you give it to your guinea pig.

  1. Chemical free, quality grass: The most important factor is knowing how that grass has been grown. You want to avoid anything that has been treated with fertilizer or pesticide. These grasses will contain high concentrations of chemicals. If your guinea piggie eats them, they could become sick. 
  2. Dry area: Next, you’ll want to avoid letting your pets forage in wet grass. If you don’t give it a chance to dry out, it will increase the risk of your piggie getting a urinary tract infection or lesions from the dampness. If you’re planning on letting your piggies forage outside, wait until the morning dew has burned off. It’s also important to avoid using grass clippings. 
  3. Avoid toxic, inedible plants: Check the type of grass and greenery that you’re going to give to your piggies. Some grasses and plants are toxic to guinea pigs. Guinea pigs should not be allowed to eat plants from the onion and tulip families as they are poisonous to this species.
  4. Fresh grasses such as fescue, wheatgrass, bluegrass, and timothy are good options for foraging. These are the most common types of grass for your furry friends to eat. Piggies like new growth the best. Experiment to discover what your guinea pigs like best.
  5. Source Out Clean Grass: Additionally, before letting them forage, check that the grass doesn’t have mold or fungus growing on the leaves.  If you have multiple pets, you need to make sure that the grass hasn’t been soiled. Often, urination on the grass won’t be a big problem. But you shouldn’t let them eat any grass that contains feces. Not only is this gross, but it also has the potential to make them sick. 


There are a few specific types of grasses you want to avoid, because the protein and calcium levels are so high. These include; 

  • Lucerne also known as alfalfa
  • Clover hay

It’s okay to feed baby guinea pigs (up to 6 months old) or pregnant piggies these grasses, because they need the extra calories.  However, it’s too many calories for the average piggie.

Introduce Grass Slowly

Your furry friends might not be used to having grass in their diet.  But, that’s no problem.  

To introduce your guinea pigs to the new food, you should start by feeding them just a bit. This allows their stomachs time to adjust. It will also give you the chance to watching for signs that they’re not feeling well.

If you still have some hay, you can mix it with the grass. Over time, increase the ratio of grass to hay. 

Foraging for Grass

best hay replacement for guinea pigs
Personally, I’m more of a grower than a forager. But, don’t let that stop you. If you have access to a bit of untouched nature, then foraging might be the way to go.

There are two ways of giving grass to your guinea pig. You can do the foraging yourself, cut it up and give it to your guinea pigs. Or you can let your piggies do the foraging themselves.

We’ll explore both options below.

How To Forage For Your Piggie

There are a few things that you need to remember about the content of grass that you’re sourcing from if you’re foraging for your piggie.

  1. When you find a gorgeous patch of fresh grass, there are approximately three guidelines that are important: 1) never take all the plants, 2) make sure the patch is not too small (choose one with a large number of plants), and 3) if you need to choose between two patches of grasses, choose the patch with the most vegetation.
  2. If you do not know what a plant is, leave it alone. There are some plants in the world that look similar to others that are harmful to guinea pigs. If you’re not sure if a plant is safe, do not touch it.
  3. Do not collect clippings from a lawn mower. If you pull the grass, it is ok. But grass cut by an electric, mechanical, or gas mower will make your guinea pig sick. When the grass is cut it starts to ferment and becomes dangerous for them to eat. Also, the grass is contaminated by the dust and oil of the lawn mower. And contaminated grass will cause  health issues for your little buddies.
  4. Be careful foraging on public property. Public property is likely sprayed with pesticides, so it’s best not to feed your fur babies from a park unless you know that none of the grass has been treated.

How To Let Your Piggie Safely Forage

You can move the enclosure outside and allow them to forage for the grass themselves. This is closer to the way that they would behave in the wild. If this is your first time setting up this system, there are a few tips that you can use. 

  1. First, you’ll want to make sure that you are using a strong enclosure or a guinea pig run. You won’t want a predator to hurt your guinea pig. If is your piggie’s first time outside, it might take them a while to get used to their new settings. The best way to do this is to start with a small amount of time outside (say about 10 minutes?). Then slowly increase the amount of time that they are spending outside.
  2. Next, you’ll need to consider the soil temperature. Remember their bodies are very small and close to the ground. If it gets too cold, there is a risk that they will get sick. Because of this, you might need to bring them inside during the winter, reverting to hay. If it is cold in the morning during the summer, keep your animals inside. Bring them outside when it warms up.
  3. Lastly, put a covering over part of their outdoor enclosure. This gives them some shade to retreat to if the sun gets too hot. It also ensures that they have a place to hide if predators or other larger animals approach. By making them feel safer, they will become more active

Other Elements of a Healthy Diet

While grass or hay is an important food, it isn’t the only part of a guinea pig’s diet. Let’s look at the other foods your pet should be eating. This table provides a good summary of these elements. 

ComponentType of FoodWhy it’s ImportantPercentage of Diet
FiberHay or grassIt aids the digestive system, encourages natural foraging behaviors, and helps grind down teeth80%
Vitamins and MineralsPelletsWhile hay and grass are good, they can’t provide all the nutrients they need. 10-15%
Healthy TreatsFruits and VegetablesThese provide some variety to the diet. It’s best if you can focus on something that has a high Vitamin C. 5-10%

To make sure that they are getting the right mix of nutrients, offer your guinea pig a proper serving of Vitamin C enriched pellets.

Guinea pigs should have 1/4 to 1/2 cup of these pellets each day. Additionally, make sure that you offer your piggies one cup of a veggies each day

Your piggie’s water containers should be filled with unlimited amounts of fresh water daily.

Frequently Asked Questions About Hay Replacements, Grass, and Guinea Pigs

What Happens If You Don’t Feed Your Guinea Pig Hay?

Your guinea pig’s health will deteriorate rapidly if they aren’t fed hay. Hay, an important part of a guinea pig’s diet, and they need unlimited access to it. If they cannot access hay for 24 hours (or more) per day, it can lead to what is called gastrointestinal stasis (a slowing of the digestive system) in guinea pigs- a condition that is fatal if left untreated. Additionally,

Can Guinea Pigs Eat All The Grass They Want?

Guinea pigs can eat all the grass they want once they’ve been gradually introduced to the varieties of grass that are safe for them to eat. The most important thing to remember is to start your furry friends off with small amounts of grass and then to slowly increase the amount you give them to enjoy.

Final Thoughts

Hay is one of the most important foods in a guinea pig diet. Ideally, it should make up 80 percent of their diet. But hay isn’t the only fiber that your guinea pigs can eat. You can also try giving them grass. This will stimulate their natural need for foraging. It can also be a good way of getting them outside. 

As a guinea pig owner, take the proper precautions to make sure your fur babies don’t get sick from the grasses.  First, it’s important to check the grass. Next, introduce it to them slowly. Finally, work to increase the amount of time they spend outside, to get them used to it.

Of course, don’t forget to provide clean water and the appropriate amount of fresh fruit (with a low sugar content), fresh vegetables (leafy greens in particular). By doing this, you’ll ensure good dental and digestive health for your guinea pigs. 

Do this and your little friends should be used to eating grass (stuffed with helpful nutrients) from your backyard in no time. 

DVM, S. L. (2015). The Guinea pig handbook. Barron’s Educational Series.

Guinea pig feeding. (n.d.). The Humane Society of the United States.

Javier Americo Campos Villarroel. (n.d.). Digestibility of legumes and grassy forages in Guinea pig feeding. BYU ScholarsArchive.

Oglesbee, B. (2011). Gastrointestinal Hypomotility and Gastrointestinal Stasis in Guinea Pigs. Veterinarian in Cumming GA USA | Cumming Animal Hospital.

What do I need to know about my Guinea pigs’ health? (n.d.). RSPCA Knowledgebase – Let Australia’s most trusted animal welfare charity help you answer the big questions.

Your Guinea pig’s diet. (n.d.). Saving pets, Changing lives – PDSA.

Similar Posts