With the heat emitters you can regulate the light easily.
I give them about a week to eat and drink day and night by leaving on a lamp with a 60 watt bulb on the desk in the room that they are housed in. On about day 7, I start turning that lamp off at night between 9 and 10 pm but do leave a nightlight on across the room.
I turn back on the lamp in the room at 6:00 a.m. and leave it on during the day. I keep the curtains closed in the room because my incubator and hatcher are in there and well and I want to keep the temp as steady as possible.
So they get about 9 hours of darkness per day.
The contrast between these babies and those that I used to raise with a lightbulb as a heat source is remarkable. They are not as "jittery", much more laid back...don't freak out when the light is turned off, etc...