[header] How to prevent lice and mites infesting your pigs [title] Cull and repopulate your herd with pest-free livestock. [step] Chronically infected pigs should be culled from the rest of your pig population. This is the best way to keep the bulk of your livestock healthy and free of pests or disease. 
However, it's important that you use only healthy pigs that are free of pests to restock your pig population so that you do not usher in a new wave of pest infestation. [substeps] Restock your pig population with pest-free stock.