The most obvious signs are changes in appetite and activity. They may lose weight (you need to weigh your pig regularly - every day if you suspect it's ill), they may have crusties around the eyes, sneeze, cough, squeal while peeing - it depends on the illness. Any change is an indication something is wrong.
If you're not sure whether your pig is sick or healthy take it to an exotics vet to find out for certain.
You can know if your piggy is hot by felling there stomach, looking at their ears.
Take your guinea pig to the vet if something seems wrong...
The gestation period for the guinea pig (I assume this is what the question is asking) is about 60-65 days.
The heart in a guinea pig is in the body cavity between the front legs. It is not uncommon to be able to feel heartbeats in their stomach area.
you can feel movement in the stomach and they get extremely fat!!
If it is harder, it is pregnant, if it is soft, it is not
It won't have thrown up - Guinea pig's physically cannot be sick.
they sqeak and the other usually sqeaks back
Take you guinea-pig to the vet - if they are experienced they should be able to tell if your guinea-pig is preggers or not.
. . . . I don't want to know if that really happened to your guinea pig. Pretty sure it can't live through that. But you shouldn't ask WikiAnswers, you should ask your vet!!!!!
A pregnant guinea pig's stomach will become visibly swollen and rounded as the pregnancy progresses. You may also be able to feel the outline of the developing pups within the abdomen if you gently palpate the stomach area. It's important to provide extra care and monitor the pregnant guinea pig closely for any signs of complications.
when your guinea pig has a sign of thinning fur or bald patches or a wet nostrils.