Feral hogs (also called wild hogs; Sus scrofa) are characterized by high reproductive potential, with a young age at puberty, large litters, and frequent breeding. 

Female feral hogs can reach sexual maturity as young as 3-4 months of age; however, most wild sows reach puberty by the time they are one year old.  Females of this species are polyestrous, being able to come into estrus every 18-24 days if they are not successfully bred.  The ovulation rate typically averages 7-8 shed ova but can range from 3-15. 

The feral hog’s gestation period averages 112-120 days and can vary from 100-140 days. (This equates to as many as 3 litters per year) 

 The newborn or neonatal litters in feral hogs average 4-6 piglets and (but) can range from 1-12.  Similar to the newborn litter size, the number of lactating teats per sow averages 4-6 and varies from 1-12.  As such, the number of lactating teats is highly correlated with the number of piglets in the sow’s litter.(Source)