Awww...

your guinea pigs are totally adorable!


Guinea pigs that are healthy really shouldn't really need probiotics, they just need a well balanced healthy guinea pig diet (including lots of yummy hay).
The vet has sometimes had to prescribe antibiotics before in the past when i've had sick piggies. And antibiotics can upset the delicate tummies of guinea pigs, so because of that probiotics were also prescribed to try and balance it again.
Hope that helped