One-way 3D printed wire chicken door, also known as a bob door. These are commonly used with pigeons. This version is for chickens. Print between 4 and 6 Tees and 2 or 3 lock bars. use 4mm wire or a wire clothes hanger to create the bars and axle. Mount in a simple frame at least 9.75 inches wide for 4 tees. Works great for getting chickens back into a run without releasing the whole flock.