Nursing tops for breastfeeding mothers.Save on Nursing Tanks!

how long does it take a female mouse to become so engorged with milk that she will be willing to nurse another?

moms litter.
they have met a few times but are in separate tanks
i weened old moms pups today (7@23 days old)
new mom has 12 (2 days ago)
will old moms tits hurt so mutch that she will be glad to help nurse this litter ?
BOB
i feed them rat&mouse pellets & hog grower pellets and when the babies get big enough i feed them to my snake.