Well it is normal for her. I have a lot of chickens that 3 years old, is an old chicken. And like animals, the reproduction tends to fall off with age.
I know a lot of people on here have 10+ year old chickens, but I have never even come close, and really do not want real old birds. I think you have a healthier flock if you add chicks and let old birds go. She would be on the cull list for me. A lot of people like to keep them even if they are not good layers, to each his own way of doing things.
People can really only give chickens a healthy diet. If her basic needs are being met, reproduction is more genetic. I would not try and hatch her eggs.
Mrs K