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Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
The pigsty built by farmers halfway up the hill. (a) The small-scale pigsty, which can hold up to 5 pigs; (b) the slightly large-scale pigsty, which can hold about 10 pigs. (Photo by Xingcen Zhao, August 2022, Photographed separately in Chongren and Zhongyuan villages).