Pigs on a normal diet should eat approximately 0.454kg. of food a day for each month of age. If you're fattening them up, increase this to up to a maximum of 2.72kg. per day. The best way to do this is to feed them little and often, at least 3 or 4 times a day. Commercial feeds contain all the nutrients necessary for a pig to put on and maintain their weight, and you just need to supplement it with a few additional ingredients.
Give your pigs free access to food and drink with a self-feeder so they can eat continuously throughout the day; however, make sure you clean the area they feed from regularly and keep it replenished. Ideally, check it twice a day so that their food is always fresh.
Add dried whey, plasma proteins or crack a couple of eggs over the top of the feed to add protein, which will encourage weight gain.
Place the food in individual containers if you have more than one pig. If pigs feed together from the same receptacle, they will bully each other and waste food.
Keep food in airtight bags so that it stays fresh. If food develops an "off" smell or flavour, the pigs will reject it.
Keep the area where the pigs live at a reasonable temperature. If it gets too hot throughout the day, the heat will encourage weight loss, so ensure there is plenty of shade, for instance.
Weigh your pigs once a week at the same time each week. Their weight can fluctuate throughout the day. If they are not gaining the required weight, try increasing their food in small amounts.
Always make sure your pigs have access to fresh water.
Never feed your pig leftovers or meat, as this can harm their health.