1. scratch is a treat, not a feed. a handful a day at most, less is better, is all you need.
2. stick to one kind of feed, what brand are you feeding, it does make a difference
3 you are also feeding a lot of scrapes,(greens, veg, so on) that is also lowering your protein levels
raise your protein and add lights, on a timer a little at a time, up to 14 hours a day. Also do the butt test to see how close they are to laying, this doesn't involve putting you fingers in you hen
pick up your bird, hold it like a foot ball, raise the tail, find the 2 soft bones above the vent to either side, place your fingers between the bones, 1 finger not laying 4+ weeks till, 2 fingers soon or just about to start, starting, 3 laying a good layer. plus look at your hens vent is it long wide and soft (laying) or little round and hard (not even close)
hope this helps
laying in winter with out light, that depends on the breed, and is there a yard light or some other light source close, plus new pullets will lay longer in winter if the have just started to lay. if you do not have light on them