Buying stores from market is as risky as from breeders in my honest opinion. When we went looking for our golden retriever we saw some of the breeders and well the less said about that the better. Buying store cattle from breeders and market and the problems I have bought in have taken years to remove.
After sales support ~ for someone starting in pigs or even been doing it a long time, information is everywhere, on here for example, it is unlikely that you are going to experience a situation that someone on this site hasn't already experienced and laughed about ... and after all if it's a serious medical problem well you're not going to make a post and then hope, you'll probably phone your vet ~ mine still does advice for free and I actually trust him enough that he isn't going to come for a whim and a pray and to give me a bill (I do understand that not all vets come into that bracket though)
Now to pig breeders ~ omg ~ having been invited and seen some of those and the conditions they keep pigs shocked even me, one of the first ones we saw certainly made me not want to buy 'high' welfare bacon ever again. I'd rather go and give money to tescos (a company that is not interested in supporting uk standards of welfare but just wants to make a profit so will buy from europe) but at least they are honest with it's all about the bottom line. Another breeder we met, one of it's pigs had mange (that one I almost got my wife to bring a change of clothes and vat of bleach to the end of the drive) and they where willingly showing these animals.
So to market, trading standards are all over it like a rash, a lame animal, I'd hate to be the auctioneer or even drover and get caught moving that off the ramp with everyones eyes / mobile phones and cameras.
And twizzel is buying weaners not stores so might not be a pedegree breed but it's a good start I'd say.
Twizzel ~ I feed my pigs milled barley and a protein mix / a higher %age than to calfs but don't use the protein you would mixed with the weaned cattle there is something in it that the piggies can't handle but I only go up to 4 lbs and hold at that amount until the 6 months point, we mix with lots of water and make a wet porridge which they seem to love and feed twice a day. If you use rolled barley then you have to soak it longer for the piggies diggestive to work (so I've been told) The pork tastes really really different to shop bought and I'm really pleased with it.
Sugarbeet they love but you have to becareful with quantities and as people have said 4lb of veg is supposed to = 1 lb of normal food
Tried sow weaner nuts only thing i've learnt from that, they are expensive.
Finally and this is the problem not all breeds of pigs are the same so prepare to make mistakes on feed (normally they will be too fat first couple of times as they love to eat and that extra veg you threw over the fence will end up in the butchers bins) but enjoy it, i find it very rewarding