Pigs will out breed deer by 10 to 20 times. A deer will have 1 or maybe 2 fawns a year. A pig in a warm climate can have 2 litters of maybe 10 piglets per year.
Three litters...one approximately every 100 days, and as one biologist put it "For every 8 pigs, 10 survive". Almost nothing kills them but people. Wolves and mountain lions are the exception, and we have no timber wolves, and few lions in the eastern half of Texas.
