I have had supplemental light in the hen house ever since the days started getting shorter, from 5 am until about 9 am, and then again, from 4 pm until 10 pm. Doesn't seem to matter to them... they have their run, where they have access to it 24/7 (about the only time I close it is when I need everyone out of the hen house, so I can muck it out)... I've been fortunate that we haven't had any predators (knock on wood), but I live inside the limits of a small city (less than 500), so just enough activity in town to keep the predators away, 24/7. The only ones we have are a couple of stray dogs that belong to the family that runs the township (nepotism runs rampant here), and I chase them off enough that they hardly come around, because they know they're not welcome. BB gun does wonders... gets their attention, but doesn't kill them. Anyways, the chickens put themselves to bed as soon as the natural light starts to fade, and occasionally, I'll see a rooster and a couple of hens at sundown in the run, but not for long. I've had no eggs since the beginning of February, with the terrible sub-zero temps here. Of course, with the weather warming up now, and the days getting longer, I'm hoping that spring is in the air and they'll start laying. I had no shortage of eggs last winter, but we didn't have the severity of the sub-zero temps then, that we had this winter, and for so long. I've got about 30 hens.