If you increase the light to 12 hours a day they will lay. What I have done when I had free range hens was have a light on a timer that came on at 4 am and went off at 8 am. That way they "got up earlier, and would eat and drink some before I would let them out loose. But I did not put the light on in the evenings so they would go to roost as it started to get dusk then dark. It is too much of a drastic change to go from light to instant dark in the evenings. They wouldn't be on the roosts and then would fly around and get hurt trying to go up on the roost.
The extra protein will help a little bit, but it is day length that is the big deciding factor.
One other thing I do with the purebred show birds is feed a hot mash in the morning, a little soupy but not too much, like thick cake batter, and they get both the warmth first thing in the morning and extra water, they might not be drinking as much as needed. Don't make a huge amount of hot mash, you want them to clean it up. If they leave some, you can just add hot water the next day but don't keep it more than 2 days or it will go sour and they won't like it. Sour is different from fermenting.
Giving them some milk will also sometimes help some to increase laying.
When we were getting real cold temps, I would dump the waterers in the evenings so I didn't have to deal with frozen blocks in the morning and they don't drink at night while on the roost anyway. So the hot mash was eaten fairly quickly and then they would go get a drink of warm water on top of that. Increase water consumption....