My chicks are 8 weeks old and have been outside for about 2 weeks. There was an existing coop on the property we moved on and the chicken door had a broken hinge on it so I was securing the chickens in every night by putting a cinder block next to the door. There is a "chicken yard" fence and a coyote fence between them and the property line. Is it essential that I lock them in the coop at night? Don't they naturally go in at night and come out in the morning? Is it a predator thing (the reason for locking them in)? Any input is appreciated! Thanks!!