How Long Is Mice Pregnancy. If the mouse is in metestrus, you will see mostly cornified epithelial cells and pmns and some nucleated epithelial cells. After the female mouse becomes pregnant, her average gestation period is 18 to 21 days.
If the mouse is in metestrus, you will see mostly cornified epithelial cells and pmns and some nucleated epithelial cells. Do not intentionally breed mice or you may risk losing the mother and the babies, which is. My cut off point is much shorter, as long as i've seen my male do the job and he's a proven breeder, then any female that doesn't produce a litter 6 weeks after his introduction is going back to the feeder bins.