The birth will most likely take place at night or when you're not looking, and be all over by the time you wake up to find little hairy piggies running around. There are not usually complications. The birth will not usually take longer than approx. 30 mins with about 4/5 mins between babies. Bear in mind that the mother will come into season again a few hours after giving birth so make sure you separate the father or any other male pigs that may have access to her. To allow her to become pregant again without at least a good few months rest to regain her optimum health would be irresponsible.