|Ginea pigs breed very easily. The young are born very developed- they can run around in just a few hours and eat solid food in 4 days! It is best to breed only if there is a demand for them- other wise you'll end up with heaps of them.
The doe (female) will come into season every 14-16 days. The gestation period is 9-10 weeks, and the doe can mate again imeidiatly after birth ( its best to give her a few days rest, but not to long or she might not get pregnant again).
The doe will have up to 5 babies at a time. You can tell the does from the bucks (males) by grabbing them and gently pushing at the base of the genital area. In a male his penis will protrude (its a little red thingy). If to fully grown males are kept together they will fight.