unexpected litter...2nd time

Question
We had an unexpected litter of guinea pigs 5 months ago due to a pet shop selling us a female and male instead of 2 males.  I took the babies to a vet to be checked and sexed and decided to keep 2 of the girls with the female we had.  The vet missexed them and now we have another litter of babies.  I have tried phoning around vets and the response is they can't reliably sex them until 8 weeks.  They also tell me they can't reproduce until then so it's ok, however, various websites tell me I should separate them from 2 weeks.  What is the correct information?  And how do I know where to take them to get them correctly sexed?  I'm struggling finding homes for these babies, I don't want any more!

Answer

Newborn baby boar  

Newborn baby sow   It's a common mistake, but the vet is wrong.  Babies can be sexed at birth. The females can come into heat as young as two weeks, the baby boars are typically not fertile until about 3 months, but that's not an absolute.

If the father is in the cage when the babies are born the mom will come into estrus immediately after delivery and ten weeks later another litter is born.  He will also breed the baby sows. That's why we keep the dads out of the cage.

Here are a couple of pictures of newborn cavies. It takes a little practice and the secret is to spread the genital area enough to see the telltale little dot on the boars and the Y on the sows.

The "dot" on the boys is actually the little penis. You can see what looks like a letter "i" made by the division of the tiny testicles and the dot is the dot on the "i" is the penis.

Baby sows appear in the shape of a "Y".  If you spread the tissues you can see the shine of the membranes inside.  

Maybe you should take these pictures to both the pet shops and the vet!