Nov 19th I notice the mice were making a lot of squeaking which I realize they were breeding. Within 8 days I notice the females are much larger. By the 10th day they are the size of golf balls, I been giving extra protein in the form of cheese and tofu which I read in other forums. I predict between 8-10th of Dec they should be dropping their litters. 6 days before the estimated date, they look like lumpy big balls of fur. If they keep growing would it mean they are going to have large litter size? They look to be 2-3 times the size of the male.