Ren Baqian stayed in the village for a day and a half. Besides spending a day subduing the crow general, he had also achieved other tasks such as teaching the villagers how to make ice and how to cure over fire.
The reason he did this was because of the difficulty in preserving food and not because of the sweltering heat. It was difficult to preserve rations in the village, and the entire village would starve if they didn't catch enough food while hunting.
This wasn't a lone example and wasn't the situation of just one or two villages—this was a problem that many villages around the Sixty Thousand Mountains faced.
However, as Shang Ping Village was located pretty close the Forest Pillar Barriers and Ya City, their situation wasn't that bad.