I have a 7 month old Japanes Chin who is bleeding from ...

This is about the normal age that dogs hit puberty.
You need to call your vet and let them know that the dog has started a heat season as they may wish to delay the spay until a certain time after the heat.
You will have 3 weeks that you have to be very careful not to let her be near a male who could breed her.
They do make little sanitary belts to help keep your home clean.
The way the cycle goes is the dogs discharge will be bloody color at first then slowly change to straw or clear color.
In about the middle of the heat time will be the worst for her to try to get to males. Remember its not just the males who want to get to the females the girls want to get to the males just as badly so you have to watch close and never let her outside even in a fenced yard without you right there watching her.
Hope this helps you!

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Thank you very much Nancy Holmes for your quick response. I will call my vet tomorrow.

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