It's a good idea to grow fruit and veg and give the waste / spare to the pigs - they'll love it and you'll taste it in the meat

But in terms of growing and,mixing the entire ration yourself... You would need to look into the legality of using fishmeal as protein. You would also need a license for mixing your own feed.
Alternative protein sources include milk, peas, soya.
If you haven't seen it already, have a look at Prof Sandra Edwards' document on raw materials for feeding pigs. You can download it from the BPA
here