The first mixed rooster I ever had was at least 2 to 3 years old (if not 4) already, and his mother was even older (perhaps 7-9? it was hard to tell). I kept both for an additional 3 years before I changed flocks for some new blood, and they were still going strong - their vitality and fertility never took a hit. You couldn't tell they were getting old by chicken standards. That rooster's eldest daughter also made it to 4 years old without problems. She would have probably gone on much longer like her ancestors had a hawk not snatched her for breakfast. Thankfully this lineage of resilient birds lives on through one of my hens, so I know at least one of my chickens will not croak on me too early. I too have started paying attention to the age of my chickens, so I'll see who lasts the longest as time goes by ^^
