I'm looking after my friends' 2 guinea pigs whilst they're on holiday. I've had gerbils or jirds in the past; have had the 2 chinchillas for 8 years and rabbits for nearly 3. But I have no experience with guinea pigs so have relied on what my friend said plus stuff I've read. I've looked after them in the summer for 3 weeks, no problem. This time I was going to bring them round to my house again but their "summer home" was damp (its my old bunny starter plywood hutch - OK for summer or indoors but does not stand up to adverse weather). My plan was to keep them in the house. My friend advised me that they prefer to be out in the run and I could safely leave them in the run whilst I was at work (10 hours inc. travelling time). These are the second pair of guinea pigs they've had and the others died suddenly and young so my friend does not have much experience with animals. I was uneasy about leaving them out unattended for so long and also about changing the temperature of their environment so left them in their own hutch, with daily visits and runs out. I went round this morning and put them in the run. I put newspaper on some of the grass (so they had a dry patch) and also the 2 plastic tubes that they love to play in. I also shielded some of the run with tarpaulin. That was at 10 o clock. I went back round at 2 o clock and they're both dead!!!! They were still warm and soft, not rigid so I presumed it had only just happened. Absolute nightmare. Any ideas on what could cause the sudden death of bith pigs?