I always check for full crops at sunset and make a mash of feed softened with water and anyone not full, will fill up before last light. I also have solar powered lights all around both of my coops and they are super sensitive, but it never bothers any of my birds. I do have 6 Cockerels that like to start sounding off a little after 5 am (still dark as first light if right before 7am), but they all remain on their roosts until first light. My girls aren't bothered by their crows. In fact this morning I had to have my daughter at school at 7:15 (she is a 3rd grader and the tardy bell rings at 7:30am) and had to leave from the school house to make it to an appointment, so I had to let the chickens out before first light. Everyone of them acted like I was a crazy person and they stayed put, I guess until first light, even the boys that were crowing over and over, and sometimes in harmony
If I were you, I'd try to make sure they were full and offer them a mash (if that's something they like, it's my birds favorite treat!) right before locking them up at night. If you're confident that nothing else is waking them up and they're truly hungry, hopefully this will help before bad habits begin taking over and your stuck with getting up in the dark or dealing with frustrated neighbors. Best wishes! I hope this might help
