I have never had real high quality chickens, I have always had hatchery hens. The longevity of hens depends on a lot of things: the breed of the bird, the quality of the breed of the bird, the climate and a bit of luck with predators.
Truthfully, I have never had a bird that lived much past 3 years. By that time, they look old, they are a little rattier, a little slower. However, I have had them just be dead in the morning. No signs of suffering, reasonably active the day before, then dead.
So depending on you birds, it may not be a real problem. Currently I have a Buff, that has raised several clutches for me, and I am hoping that she has one more, but I won't be surprised if she does not make fall, she is currently 3+ years. Red - a egg giving girl, a cinnamon queen, laid an egg nearly to the end, just a couple a week at that point, and one morning she was dead.
So, what I am saying is it might not be a big problem. Personally, I am attached to Butter, but I know her time is close, I like to add birds to the flock, and birds have to come out. Pick a favorite, and keep her through her old age, culling if she is not well. The others, let them go.
Mrs K