I am new to owning guinea pigs and I thought it would be a good idea to join a forum because I constantly feel like I have questions. We got two female guinea pigs from petco last week. I know it was probably a bad idea to get them from a pet store in the first place. They were both a couple months old. Anyway, the one my brother selected was a bit small.. you could definitely tell she was a runt. For the first couple of days they were a bit shy, but ever since then they have seemed okay. Axel, the bigger one, has been extremely hyper and will run laps haha and she has been eating fine. Paige, however has always been much quieter and never seemed active ever. I should've seen the signs, but i thought it's just because she needed to catch up with axel.. i figured she was younger. This morning.. I went to feed them and found Paige dead. It was really heartbreaking because we didn't expect it at all and we've formed a bond with this pets already. :( We've already scheduled an appointment with the vet for axel to make sure it wasn't some type of infection that took paige. I just want to know why this could've happened? could there have been a birth defect? she ate just fine... i just don't know what else we could've done.