If you already have a fence, tie shadenet green color upto 3 feet from ground. Other end should be buried in ground so that it is stretched and tight. Shade net is cheaper item, you get it everywhere. The wild pigs feel that it is a net to trap them, so they stay away from it.
We also have wild boar problem here in Karnataka and my farm is 2 kms from Bandipur forest range, so have elephant and wild boar problem throughout year.
This year we tried with shadenet and it worked beautifully. We had tried earlier with barb wire and solar electric fence, but those pigs dont feel a thing.
After we did, many farmers have adopted same approach with good positive results.
Another slighlty costlier solution is to have a narrow trench around the farm, at least 3 -4 feet deep. Wild boars will not enter as they will be afraid to go down the trench. These trenches can also serve as rain water harvesting where you can channel the water to some pond.