Is it a bad idea to put another female guinea pig with two sisters and their mom?
um well no. it should be ok. i have a 6month old girl and a 4year old boy guinea pig and we are going to mate them. yes it's ok. make sure the female is under 10mnths old if youre mating her for the first time as the first litter has to be before then or there will be big difficultys at birth where her birth canel has developed and the babies will get stuck which will result in there death and maybe the mothers. girls fight together so prob not good idea!!