It is amazing isn't it? It actually takes a guinea pig longer, they have a 70 day gestation! Chi puppies tend to come early because Mother Nature is very clever and they would get too big to be born naturally (especially with a small litter) if they stay in for the extra week. The fact that this mummy to be has gone to 62 days makes me think she is having a large number of smaller pups. So hopefully she will be able to deliver easily, unless she has so many in there that the uterus is too stretched to produce contractions.