How to prevent pig backflow by driving multiple pig channels

Design a passage for pigs. When driving pigs, artificially design a passage for them, and the wall of the passage is preferably a solid wall. If it doesn't work, you can use temporary walls, such as iron railings instead, colored cloth strips instead (or feed packaging bags sewn into cloth strips), or other opaque wooden boards to let the pigs see that it is right to just go forward, so that the pigs will follow the route you designed for them. It is easier to catch a large group of pigs than to catch a pig, so it is very important to keep a group of pigs in formation when catching pigs. Never raise a pig at once.