Boars, un-neutered male pigs, become fertile at six months of age, long before they are completely physically mature. Pot-bellied pigs are considered fully-grown by six years of age, when the epiphyseal plates in the long bones of the legs finally close.
Because pot-bellied pigs are the same species as ordinary farmyard pigs and wild boars, they are capable of interbreeding. Most pot-bellied pigs have been crossed with various farm pig species. A 2004 study by Thuy revealed extreme genetic diversity in indigenous Vietnamese Pot-bellied pigs. The purebred pigs had more alleles per gene locus and a large range of allelic sizes. They were also genetically different from each other according to location of origin in Vietnam. Pig breeds from developed countries were refined over centuries to a specific genetic make-up. This means a cross between a purebred Vietnamese Pot-bellied and another pig type, its genetic material is more diverse and the offspring will resemble the more specific pig imports. The German Agriculture Ministry has been assisting Vietnam with its pork production by introducing large breeds of pigs into Vietnam since the mid-1980s.