If you have room, you might consider adding an extra nest box or two, away from where your broody has set up housekeeping. You don’t need anything fancy. A plastic dish tub in a cozy corner would work, or something similar.
Have you candled the eggs? You should see development by 7-10 days. If...
They need (if I remember right) around 12 hrs of light in order to lay very much. I may have missed it if you said whether you’re supplementing their light. If you choose not to supplement light (which many do choose in order to give the girls a break) then you’re not going to see a lot of eggs...