my chi is 9 months old and she just started her menstruation period. we were wondering because her private part has gone bigger... we just want to know if this is normal or if we have to take her to the vet....thank you for your help.
Yes, this is very normal. It is called a "heat cycle", most female dogs come into "heat" twice a year. It is usually around six to nine months of age. She will be in for about three weeks and her little "privates" will be swollen. She is to young to be bred (my opinion). It is better to wait untill she is through her cycle and then have her spayed. You can buy little "panties" for her to wear to keep her from bleeding on furniture, people etc.
It is definately normal - but please consider spaying your baby once her cycle is finished as it reduces the chance of getting certain cancers drastically. Also no that they have swollen they will not return to the sive they were originally hence another reason why people usually spay before the first heat as it is more aesthetically pleasing.