Being a real newbie with pig(lets).
Even though Blinkers gave me a guide to how much my piggies would eat i found they didn't eat as much at the start, less than the 450kg each sugested at 8 weeks, possible because they were too busy digging up my beautiful lush grass chicken pen (temporary accomadation) and finding allsorts of 'what ever piggies find to eat in the dirt'.
They have 2.5 scoops each twice a day now but only if they clear it up with in 30mins of putting it in the trough (think some goes to the birds) otherwise I cut it down/put it up depending if they clear it up, haven't actually measured how much they are having now, just go by how quickly they clear it up; with boiled spud and a bit of bread and any vegies/apples etc at lunch time as an extra. Night time when i shut them in they get another 'clover butter' tub of nuts.
They seem happy enough - digging, playing, lying about in the sun or out of the wind in their shed, putting on weight, don't think they are too fat - will check what Sallyinthenorth said about the fat over the ribcage - and their poos are normal.
I'm sure they would let me know if they aren't getting enough.