gestation period for mice
Female mice come into estrus (heat) every 4-5 days (this is the time they will be fertile and receptive to a male). They will have a fertile estrus within 12-28 hours after giving birth, and within a couple of days of weaning a litter. Length of Pregnancy: The gestation period of mice is usually 19-21 days.Note: mice can breed shortly after giving birth. If they breed while already nursing a litter, the gestation period can be longer (around 28 days).Litter Size:Litter size is quite variable; 7-12 pups per litter is considered average but more is not unusual (20 in a litter is quite possible).ote: mice can breed shortly after giving birth. If they breed while already nursing a litter, the gestation period can be longer (around 28 days). Litter Size: Litter size is quite variable; 7-12 pups per litter is considered average but more is not unusual (20 in a litter is quite possible).