I have two barred rocks and an australorp who are 7, so it's possible to have elderly hens toddling around on your lawn. The good thing is they don't dig up the lawn like the young girls
Miracle of miracles, the a australorp started laying again this summer, so you might even get a rare egg from them. As a rule of thumb the hybrids die first. The "fancy" birds, like the Polish, seem to keep laying for years, but they don't lay much! It is expecting too much for the hens to live to ten. That is ancient for chickens. My favorite poultry book, a manual from 1895, suggests never keeping hens past 18 months, so this idea of keeping hens past their prime is a new invention of backyard pet hen keepers. I don't follow Mr. Biggle's suggestion, but I also don't have unrealistic expectations of the longevity or health of my older hens. (BTW, I write a lot in my blog and my FAQs about old hen keeping. see my web site, HenCam.com)
