Guinea pig weight: a weekly weigh-in is your best early warning

As prey animals, guinea pigs mask pain and illness. According to the MSD Veterinary Manual, they hide the signs until they are very unwell and can go downhill very quickly: early treatment often makes all the difference.

According to the PDSA, regular weighing is the best way to check that they’re eating properly. A drop on the scales often comes before visible signs: dental problems, digestive trouble, infection or a lack of vitamin C.

• Every weekOn the same day, at roughly the same time.
• The same scalesKitchen scales accurate to the gram; put your guinea pig in a small tub and subtract its weight.
• One weight eachIn a group, weigh each guinea pig separately and record the result under their name.
• Write it downRecord every weigh-in: it’s the comparison from week to week that tells you something, not a single figure.

Pick them up calmly with both hands, one hand under the chest with their front legs either side of your fingers, as the RSPCA describes. Don’t handle a newly arrived youngster straight away: let them settle in first.

Stable weight

A good sign in a healthy adult.

Weight loss

According to the PDSA, it can be a sign of illness. Check they’re eating their hay, look at their teeth and droppings, and call your vet if it continues.

Weight gain

According to the PDSA, a possible sign of too many pellets or too much fresh food. Talk to your vet.

Rapid change

Significant weight loss or gain over a short time is one of the signs to report, according to the PDSA.

The RSPCA advises also assessing their body condition, using a scoring chart, to make sure they’re neither too thin nor too fat. Ask your vet to show you how to feel for it at the annual check-up: you’ll know what your guinea pig feels like at a healthy weight.

• Unlimited hay, a small portion of pellets and vegetables: it’s too many pellets and too much sugar that cause weight gain.
• Fruit and treats stay occasional.
• Exercise every day, with space, tunnels and supervised time out of the enclosure; no exercise wheel, which can injure them according to the MSD manual.
• Being overweight makes sores on the feet (pododermatitis) more likely, according to the PDSA and the MSD manual.
• For an overweight guinea pig, your vet will set the plan: never cut back on hay.

Log every weigh-in in MyArk: the chart shows the trend at a glance, for everyone in the household, and a drop shows up before it’s too late.

• A weight chart for each pet, over time
• A weekly weigh-in reminder
• Meals logged by everyone in the household
• The latest weight to hand for your vet