my female mice keeps biting my male mice HELP?

seperate them now otherwise you are going to be overrun by babies

the female is more than likely biting the male because

a] she is pregnant, near to nesting and trying to drive him away

b] she is not on heat and he wants to mate

c] she is in early pregnancy and he still wants to mate

if and i suspect its a big if, you have always kept them together and had no babies that means EVERYTIME she has been pregnant she has reabsorbed the babies through stress this is not good psychologically

move them to different cages, get her a same sex friend or two, female mice live happily together

HE however will have to live alone, it can turn very bloody and nasty trying to introduce two male mice

I raised mice for many years and it is very bad. You did the right thing by separating and you will never be able to put them back together. Mice do not make one another bleed as part of a mating ritual. If your goal is to breed mice, a ration of one male to two females is ideal (this is based on research findings).

I've had hamsters before, but I think this also concerns with mice too. Females need their space, so if there's males or other female strangers intruding their space, they will defend and fight for it. It is like their home and there are intruders inside their home. For breeding, it's better to place a female into the male's cage or space instead of the other way around. Females are more aggressive in defending their space, thus, they bite the males.

Separate the males and the females. They should not be housed together because they will breed rampantly and you may end up with dozens upon dozens of baby mice, who will in turn interbreed with their parents and siblings.

I don't really own mice, but I would suggest putting then in separate cages so they can't bite each other.

Take her out of the cage and a day after put her back in so she won't be territorial because he was in the cage alone.

Serperate them. I had to do that with two of my gerbils because as they got older, they weren't as friendly towards each other. It's only a little bite right now, but they could end up killing each other. I wouldn't risk it.

you need to keep the mice apart, till you need to breed them

she is behaveing like the alpha female , the leader

they need to be separated...probably for good. One will eventually end up putting small bloody wounds on the other.

she is being territorial