No, the hens are not 4 yrs old, but the last 3 yrs where I had chickens I never needed a light. before that I lived in germany and there my ten, 13 yrs old aussies never needed a light to lay either. The hens themself are right now 9 months(black stars that still haven't started laying) and 1.5 yrs old.
I dewormed and debugged about 2 months ago and they look all awesome,besides the leghorns(4 of them), those are still molting.
Today one of my old banties(8 yrs old) surprised me with an egg, the first one I've seen in months, and she doesn't get fancy layer feed or any extra light....... That means I'll at least get 1 banty egg each day from now on, this hen is better then any of those commercial layers, 8 yrs old and lays like crazy when she isn't moulting or broody.