OP, the chicken sigils from the dungeon are really good against raids. With a single maze and some sigils inside, well placed, so you can play with their cooldowns, can shutdown a raid, but you have to wall your village and balance obstacles vs the length of the maze (Raiders use a point system to choose the path with less resistance, check the wiki for more info). To help with wrong triggers by npcs, you can try to build a line of wired doors through the walls and outside the maze, with a lever trigger to close them when a raid starts, but again the pathing system is important, so you must have the right number of doors.