Your birds do seem a bit old to have never laid an egg. It's not unheard of, though. Have you searched everywhere to make sure they aren't hiding eggs from you? If you free range, try keeping them up for a few days, and see if you get any eggs. Also, try putting some golf balls or fake easter eggs in their nestboxes.
If not, then the bottom line is that they are coming to the point of lay at the end of the laying season, and daylight hours are decreasing. My adult hens are starting to lay fewer and fewer eggs because of it. Soon they will stop laying altogether, since I don't supplement light in the winter. (I do have a couple of hens who will lay through the winter, for whatever reason.)
There is a possibility that you won't see any eggs at all until spring, unless you give them some extra light.
I'm no expert on how to do that, since I don't do it myself. I have read that some people put a regular light in the coop, on a timer so it comes on very early in the morning. I'm unsure of the wattage required. I believe it has to do with the size of the coop.
I'm sorry you aren't getting any eggs! It happened to me last year with a small hatch of Dominiques. They waited until spring to start laying. The silver lining was that they never laid the small pullet eggs I expected. They were so physically mature, they just started popping out big girl eggs from day one.
Good luck with your girls. I hope you find a hidden stash of eggs.
