Through winter, when fresh food stuff is scarce, then you have to feed more pig nuts. especially as the pigs are burning more to keep warm. I will boil up big pans of whole spuds in winter, unwashed. the pigs love them. In summer obviously more fresh stuff is available, and it is warmer, so no spuds. Loads of green stuff, from veggie patch ( i plant too much of everything on purpose), and less pig nuts. I don't like my pigs to be too lean, or too fatty, so i have to adjust accordingly. I have looked at a cheaper source of pig nuts, but they used gm maize, soya and wheat and i stayed with my usual supplier , which use natural products, but not organic. I figure that if the pig has a good out door enclosure with loads of grass and weeds in it will get plenty of execise and nutrition with a twice daily feed of pig finisher nuts and flaked grain mixed.plus veg plants and weeds chucked on for them to graze on. the options are infinite, as long as you achieve a growth rate that suits and a healthy happy pig.