i dont know if our guinea pig is pregnant

Question
how can tell if a guinea pig is pregnant
we had recently taken in three guinea pigs because they were abandon. two were male 1 female. all are quite young. we got them about four weeks ago. and i really don't know if she is pregnant or not. please help  

Answer
Guinea pigs can get pregnant quite early (like at 4 or 5 weeks of age), and if a male and female are together it is likely that the female with get pregnant. I'm afraid I don't know of any signs of pregnancy, though. In the later stages the sows get really fat, but in the beginning it might not be so noticable.

It's very nice of you to have taken in the abandoned pigs! :)