Speak to Eli at the farm north of Port Sarim to start the quest. He will tell you about bacon, and give you a sample of it. Eat the bacon, then tell him what you think of it. Eli will want to tell everyone that pigs are no longer useless animals. A cutscene will play to further the story. Multiple locals want to taste more bacon after Eli gets them addicted. The locals begin to lay butter on the pigs, so Eli wants to make decoys to distract them.
Eli will give you a bacon heap and 9 planks. You must build decoy pigs on the hotspots that are in the field. First add the planks, then add the bacon for all 3 spots. You will need to continually add bacon to the decoys until Eli get rid of all the pigs. Once all the pigs are gone, Eli will take you to his cellar. Talk to him and he will tell you that he wants to train his pigs to get peoples attention. Answer whatever you want, and go see Martin the Master Gardener.
Talk to martin, who is located in Draynor Village. Ask him to take one of his piglets. He will say that he has been pickpocketed and he wants to to give the culprit a beating before he gives you a pig. Head northwest and talk to each person. Accuse each one until you guess the correct one. There is no penalty for guessing incorrectly. Martin will order you do punch the culprit. However, they complain that its not enough. You go to a cutscene that shows a kitten and a pig, while you can listen to you beat up the culprit. After the cutscene, Martin will give you the piglet.
. Go back to Eli, who is in the cellar and give him the piglet. Eli will ask you to make a machine to train the piglet into a full pig. Click build on the machine, supplies are provided for you. Eli will then ask you to get him 5 wheat. This can be picked from any wheat field, NOT FROM THE GE. Once you have 5 wheat, head back to Eli, who will explain that the addicts fall asleep. Go back outside and put bacon on the pig decoys, then drug the bacon. The addicts will not fall asleep however. Head back to Eli and he will say it takes time to work.
Grabbing Some Onions
Eli will then ask you to get 5 fresh onions. Once again, these have to be picked from a field and NOT the GE. The closest onion patch is South of the Draynor Village bank. When you return to Eli, you will notice that the addicts are gone, and the pig has grown. Hand over the 5 onions, then train the pig on the machine. A cut-scene will play, showing the pig entering the machine. The pig will come out with equipment related to the machine you made.
After the pig has entered the machine, Eli will ask you to take the the Lumbridge Castle, the Varrock Marketplace, the Ardougne Marketplace and northern Falador. He will give you a sheet of paper to track which cities you have visited. Teleport to Lumbridge, then walk your pig to the castle. A cut-scene will play where you explain the benefits of having a pig. Do the same for the other 3 locations. It doesn't matter what order you visit the cities. Once you have visited all four cities, return to Eli for your reward.
Congratulations! Quest Completed!