My kids had guinea pigs. They are so cute. We fed them pellets of some kind. I think we got them at the pet store. However we found out not to use plastic bowls as they will eat them (plastics are made from soybeans). Their little ones are born with eyes open and a full coat of hair and start eating the food right away. We used wood shavings for their pens. My youngest was bitten by one and it was quite painful but they are generally not aggressive.