I’m sure an old chicken needs more time to recover than a young chicken. But not many chicken owners have chickens old enough to compare them with people of older/old age. Many people think a 5 yo hen is old. But knowing they exceptional can get 20 years old (like 105 in human age) and they can lay eggs until 10 yo (fertility of woman stops at 40 - 55) put a 5 yo hen in another perspective.
Following such a scale, the 5 yo chickens are still quite young and my 10 yo chickens are about middle aged.
Looking at their early development you get another picture. Mature at about 6 months old is normal for a hen. Humans are still children at 2.5-3 years old. Or should we count the embryo phase too?
No sense scale:

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1=5.2
5=26
10= 52
20 = 104