Heather, feed wise as Nellie says really. Very important not to overfeed otherwise you run the risk of possible health problems with your pigs as well as being a total waste of money to put your euros into fat!
Lice are a Tammy problem - they are flat black little insects that bury their heads under the skin and cause terrible irratation to your pig. Pigs love to scratch anyway but a pig with lice will start to lose their hair and feel very uncomfortable. You can usually spot them aroung the neck area and ears. If a pig is too infested they will spread down the back and into the ears. We sent a young male out for stud to someone who we thought would look after him. He was returned to us lousy! Inside his ear were black with the lice and his body covered. A quick fix was a liquid coaltar which we got from the vet. You dilute per the instructions - using gloves - very important - sponge the liquid all over infected areas. You can be quite liberal over the body but it is very important to squeeze out the excess before going near the ears, then wipe around the ears, inside and out if necessary, sponging the area carefully, avoiding the eyes. It kills them within an hour - it works very fast. Thereafter just keep an eye open for any more signs. If they have already had them then another tale tale sign are eggs around the neck areas which are like tiny little white droplets.
Worming as Nellie describes also - can be bought in a powder form from the vet and give in a sandwhich or small amount of Farrine D'orge.
We personally inject an antiparasite injection which treats for all parasites internal and external which we administer every four months. Having said that this has been a bad year for mites so important to check regularly. The injection can be bought from the vet over the counter in single doses. It is important that there is a period of around 60 days after giving this treatment and before finishing.
On a small scale it is probably better to give the powder treatment and use coaltar if necessary. We have so many that the injections are more efficient for us.
Good luck and keep us posted. Any other queries just ask, there are lots of knowledgeable people on here.
Kate