*2.1. Sample Site*

Funing County (located in Jiangsu Province) was selected as it is a famous pig farming base in China (Figure 1), known as "the hometown of piglets". Pig farming is an important source of family income for farmers in Funing, and more than 50% of the pigs were produced by small-scale household farming. As small-scale household pig farming where VAs are directly used by farmers will persist over a long period of time in China, investigating the use of VAs in Funing has important practical significance.

**Figure 1.** Location of the survey area in China. Note: This is merely a schematic diagram and does not cover the issue of territorial sovereignty.
