We use a flood light, right at about 60 watts(?). I used that bulb because it was close by. Just any old light bulb will do, nothing fancy. I would judge the wattage by the brightness in the coop. Don't want to blind the poor things.
As far as time, ours comes on at about 4 am, goes off at about 9, back on at 4pm and off at about 7pm. Some don't have their light on at night, we free range and it seems if they don't see the light, they don't go in, just wait outside. I have heard that they don't have good night vision and having the light on into the evening keeps them on the ground longer so they may not be able to see to jump up on the roosts. I have never run into that.
