If you are only wanting pigs forn a short time you will presumably be buying in growers. This will give you a chance to try out the best pigs for your land/diet.
We run our woodland pens on 'one in one out' basis. Younger grower introduced when finished pig goes off to slaughter. If you want a consistent supply of pork this is essential as they will take time to make weight. None will ever be alone and you wont get a massive glut of meat that will just end up in the freezer for too long if you kill out too much at once.
If its sausages, hams and bacon you want, I would still recommend keeping one on. Young pigs make good pork, older ones make better sausages and ham