A mouse will ovulate every four to six days, depending on the mouse, the environment, and other factors. This is when the mouse is going to be able to respond the best to a male’s advances. Due to this quick ovulation cycle, they often have a couple of litters each year if it’s a successful year for mating. If not, they might have one litter, or not have any litters at all.
This quick cycle also makes them an incredibly quick breeding animal.This leads to the mouse being quite a hard pest to get rid of if they happen to get into your house. There is little you can do to stop a mouse from breeding, and they will breed with any male they know well enough.