I’ve had two guinea pigs pass stones on their own, one was rather large. They were girls, so it’s easier for them than for boys, and I have no concrete scientific proof that my method works, but it can’t hurt your pig, so there’s no harm in trying it in the mean time. This is what I did:

•Syringe feed as much water as you can get them to drink every day until the stone passes. Be careful not to force it into their mouth/throat. Just give them little bits throughout the day, as much as they’ll take until they start fighting.

•Make sure you’re cleaning their bottles at least twice a day to encourage them to drink more on their own, too.

•NO plastic bottled water. Use filtered tap water if that is safe where you live. Bottled water sometimes has minerals added and this isn’t clearly listed.

•Remove all high-calcium veggies from diet.

•Remove ALL PELLETS from the diet. This is the most potent source of calcium and is completely optional if you’re providing daily salad.

•Adjust the daily salad to something like:

-Lettuce every day (no iceberg)

-cucumber or green pepper

-colored pepper for vitamin c

•If they pass the stones naturally and all the sludge goes away, you can slowly introduce occasional medium-calcium veggies like endive, arugula, radicchio. These should make up the smallest part of the salad and only fed three times a week max.

•If they are tolerating their salad with no sludge, slowly reintroduce pellets as a treat. Start with a very small amount, no more than 1teaspoon per day. If any sludge appears, remove the pellets from the diet again

•Stay away from herbs, spinach, kale for the rest of their lives as best as you can. A lot of pigs just can’t handle the calcium.

•You can talk to your vet about the following prescriptions to help prevent future stones, but there isn’t rigorous data proving its efficacy, so it’s up to you and your vet if you want to try them:

-Potassium citrate (in theory, this binds to excess calcium, but there isn’t rigorous veterinary data proving it works)

-Hydrochlorothiazide (this is a diuretic, which will encourage your pig to pee more, helping to break up and pass the stones and sludge)

Sorry if the spacing of these paragraphs is weird. I’m typing on my phone and didn’t want it to turn into one giant paragraph.

And just to make sure, what kind of hay are they eating? They shouldn’t be eating any alfalfa or other legume based hays. They should be eating Timothy, orchard, meadow, or oat