I had two Guinea pigs, both were about 5 years old. My first guinea pig developed a condition where she couldn't move her hind legs. It never got better and after about 7 months of daily moving her around she passed. When my second guinea pig developed this same condition about 9 months later I became very concerned to say the least. I researched online and read about the Calcium supplement available in Canada. I thought that maybe too long to wait to get here so I went with a liquid Calcium supplement from Target. It was amazing! I can't say enough about this treatment. It's been a month since I first starting giving her this supplement and she is literally running around the cage again. Thank you so much to the people out there that posted this information since the Vet never mentioned this. One thing I noticed was that I wasn't giving her as much "Hay" as before and mostly just the pellets with fresh vegetables. I noticed that the pellets didn't contain Calcium and the hay does. Hope this helps someone else in the future who may have this condition.