Why do rural people kill pigs at midnight?

It is said that there are not many pigs killed in the middle of the night, not to mention other places. Most of us get up early in the morning to prepare, we can kill them in the morning, and we will eat pig-killing rice until noon. Or kill the pig in the afternoon. If you are busy for a long time, you will get it in the middle of the night and sell it the next morning. But now there are not many rural pigs and private pigs! ! !