My 2 guinea pigs died, 1 after the other in less than 2 weeks :(

Question
I don't know why my 2 guinea pigs died. I kept them outside because the smell was really bad, but they always had food and water. They told me rain wouldn't affect them, that's why recently, when here in Miami it was pouring for like 2 days straight, I didn't worry much because I had checked that they were covered and had food. Still, with the wind, they took a little bit of rain, not too much tho. Less than a week after it rained, I came from work as usual to feed them, and I found one of them laying and shaking like if she was having an epilepsy attack or something. I tried petting her give her some food, but within 5 minutes she died in my hand. The other guinea pig was fine, but I was scared so I decided to bring her inside. I got her another companion, and within a week she started feeling down, so I put children's motrin in her water and she was fine again. But then yesterday when I went to clean their cage, I noticed she had trouble walking so decided to take her out and check her paws. When I took her out I was in shock to feel how skinny she was! I cleaned her up, put her in a separate cage with water mixed with half a pill of children's motrin and fresh food. I came home today and she was dead already. I will go ahead and get a companion for the first companion, but I want to know what they died so I don't make the same mistake with the new ones. They are all sisters, fairly 4 months old. Where I buy their food, they sell me the same food they feed rabbits with. I don't know if that is a problem. Thanks in advance.

Answer
Karla,
with them being exposed to the elements outside there's really no telling what could have happened. My only conclusion that I could make was they died of pneumonia since they both died so suddenly. I'm so sorry that they died. Generally, when it rains it's best to take animals inside so they won't get sick.