Mine don't usually. As a matter of fact, it seems as if all of the mothers pitch in to help raise the babies.
On occasion, a mother mouse will eat her babies, but it doesn't happen very often. I think I have only had a couple of mothers that did, and they were fed off. I don't tolerate that behavior. Any mouse that is caught cannibalizing, becomes snake food.
There is one exception to this. Sometimes first time mothers will cannibalize their young. I will not feed off a first time mother for doing this. If she does it after her second litter, that's another story...