There are lots of options when choosing a harness for your pet pig. There is no right or wrong answer, as long as it fits YOUR pig comfortable. A snug fitting harness will make all the difference in being escape proof. Nobody wants a pig running down the road frantically. Most will say a harness made specifically for a pig will fit your pig best with less chance of escape and less rubbing. Others are comfortable using a dog harness for their pig, either a step in harness in A frame or a H frame harness.
Although not custom made many use Nylon Non Pulling Dog Harness which can be purchased on Amazon or picked up at local pet shops.