Caring for older guinea pigs

Dietary needs in older guinea pigs

Guinea pigs, like rabbits, are hindgut fermenters. This means they rely on a diet that’s high in fibre to keep their gut healthy and moving as it should.

For most guinea pigs, a good balanced diet looks like:

• Around 85% hay or grass
• 10% fresh plants or leafy greens
• 5% guinea pig nuggets

As guinea pigs get older, their needs can start to change. You might notice they become less active, especially if they’re dealing with pain or stiffness. Over time, this can lead to muscle loss around their back end, so they may look a bit “skinny” there, even if they’re carrying extra weight elsewhere.

Extra weight can put pressure on their heart and joints, making it harder for them to move around. This can become a cycle – the less they move, the more weight they gain, and the harder it becomes to stay active. It can also make it difficult for them to groom properly or eat their caecotrophs (soft poo), which can increase the risk of sore feet (commonly known as bumblefoot).

On the other hand, some older guinea pigs lose weight. This can be linked to dental problems, gut issues affecting how they absorb nutrients, or conditions like kidney disease.

That’s why keeping a close eye on your guinea pig’s weight really matters. Small changes can be an early sign that something isn’t right. Adjusting their food, especially nuggets, can help keep their weight steady, but if you notice ongoing weight loss or gain, it’s important to speak to a guinea pig friendly vet. Getting support early can help keep them comfortable and well for longer.

It’s essential to maintain a healthy weight for all guinea pigs, especially as they get older as it can be harder to manage. Try to keep your guinea pig at a body condition score of three if using the five-point scale (guinea pig Size-O-Meter) and you won’t go far wrong.

Underweight guinea pigs

As guinea pigs get older, they can find it harder to get the nutrients they need from their food. If your guinea pig is losing weight, it’s important to speak to a vet first to rule out any underlying health issues. They can guide you on the best next steps to take.

Guinea pigs still need the majority of their diet to be made up of hay or grass (around 85%), with forage and/or leafy greens making up about 10%.

Here are some tips for getting a guinea pig to eat more of the good things:

• Try them with different types of hay or treat hay, this will help them to still be as excited as possible for eating it
• Readigrass can help with weight gain as it’s more nutrient rich than hay. It’s best used short-term as it’s high in calcium which can cause bladder problems.
• Increase forage This can help boost intake but introduce more slowly to avoid tummy upset.
• Use dry forage (from pet shops or bought in bulk) by sprinkling it around their enclosure or mixing it into hay. This encourages natural foraging, keeps them moving and can help them eat more hay.

If these changes don’t lead to a steady improvement, you may need to increase their dry nuggets as a last resort. This should be done carefully, as nuggets are very rich and can make guinea pigs feel fuller, meaning they eat less hay. Over time, this can lead to dental or gut problems, as well as increasing their risk of flystrike if they get a dirty bottom.

Overweight guinea pigs

Being overweight can put extra strain on your guinea pig’s body. Before making any changes, speak to your guinea pig friendly vet to rule out any medical reasons for their weight gain.

If your guinea pig is otherwise healthy, it’s helpful to look at what might be causing the weight gain.

• Do you have their diet right? Guinea pigs will often choose higher calorie foods over hay. Too much of these can lead to weight gain. They only need around an eggcup-sized portion of nuggets each day and should always have plenty of hay/ grass. Sugary fruits and vegetables like apples and carrots should only be occasional treats, if given at all. Avoid brightly coloured shop bought treats or seed sticks, as these are often high in sugar and contain unsuitable ingredients.
• Are they getting extra treats? Sometimes treats can be given without realising the impact. If this is happening, have a gentle conversation with the person giving your guinea pig the treats about why sticking to a planned diet matters. If someone wants to spend time with your guinea pigs, they can hand-feed safe forage from the garden or their carefully weighed out nugget ration. No one needs to be missing out when on a weight loss plan!
• Is the guinea pig being as active as they were? If not, it’s worth checking in with your vet. Pain from arthritis, joint issues, urinary problems or sore feet due to pododermatitis (bumblefoot) can make movement uncomfortable. Staying active helps keep your guinea pig at a healthy weight and supports their overall mental wellbeing.

Water – Guinea pigs, like all pets, should always have access to clean, fresh drinking water. Traditionally, guinea pigs have been given water in a plastic drinking bottle as it saves space and keeps bedding dry. Giving your guinea pigs access to a bowl is a more natural drinking position encouraging them to drink more water.

Placing more than one water source around their enclosure can help older guinea pigs who may not want to move as far to drink.

Modifications needed for older guinea pigs

Housing

As guinea pigs get older, the most important change is to their housing. If they already have permanent access to a space that meets the minimum standards for a hutch or indoor cage, plus an exercise pen (indoors) or secure garden run, no major changes are needed.  See our guide, How to house your guinea pigs for further information including minimum sizes for each size of group.

Weather proofing

Older guinea pigs can get arthritis, which is worsened by cold and damp conditions.  If they live outside, make sure their home is warm and dry. For hutches, it’s best to bring them inside from October until the end of March. You can find out more in our Winter care tips for guinea pigs article.

Sheds and wooden children’s playhouses

These are ideal for housing guinea pigs once converted. Adding insulation like washable cotton rugs, fleece blankets or vet-bed helps keep them comfortable. Cardboard boxes or small hutches with a door removed for access are great to fill with hay for them to snuggle and keep warm in.

Levels

Guinea pigs aren’t good climbers and should not have levels in their enclosure.  Plastic enrichment items such as igloos should be covered with a small towel to provide plenty of grip to prevent them slipping off and hurting themselves. It will also provide extra insulation.

Ramps

Ramps are tricky for guinea pigs because of their short legs. Steeps ramps in double tier hutches can be very difficult to use and unsafe. If ramps must be used in an enclosure, make sure it:

• Is long and shallow so they can shuffle up easily
• has a surface they can grip, like wooden struts
• has sides to prevent falling.

Any high up levels should have a barrier across the front to prevent them from jumping or falling off (see below).