I don't think any of my silkies have ever been more than two fingers wide. And quite sure that my bantam araucana, serama and moderns would not be a full two. I honestly don;t think the spacing varies based upon laying or not; it does vary based upon gender. Now comb colour can help unless you have a gypsy faced breed or black skin like a silkie, and moist versus dry vent can help.
My large fowl layers will all go 3 fingers when laying; after they don't lay a couple weeks or longer they are down to 2 fingers or less. When I lived in Tx and didn't have the dog problem I have here I would go through my layer flock a couple times of year and any old girl that wasn't laying spent a week in a rabbit cage on an empty garden bed eating weeds and bugs. No egg in a week and off to the stew pot she went. These would usually be girls that were three years old or older. Back then I usually just bought new chicks in the spring from the feed store. Now I am interested in how long they might live and still lay as well as breeding so will be doing things a little different.