The average life span of a chicken is eight years. On the more extreme end of the scale are chickens who live fifteen years. Of course, there are exceptions to every rule. The same holds true for people. The recent death of a person who was aged 128 verifies this!

Battery farmed chickens tend to live for not as long as those who are free to roam. Chickens who are in the open are more susceptible to being killed by foxes, coyotes or other hunters. Therefore it is important to try to protect your chickens with an effective fence. Many chicken farmers find that even their best efforts fail in the face of a predator's determination. Therefore, they come to expect a few lost chickens.

Looking after your chicken well will benefit its life expectancy. Be sure that it has a warm shelter and a clean place to roost. Also important are adequate exercise, and a nutritious diet.

 Eight years is a fair average, but the usual predators are not the only worry, always make sure you provide roosts off the ground and watch for skunks, possums, feral cats and ants, especially fire ants, if you are in the south. A lidded pen for overnights can deter night raiders, as do fences with the lower edge burried.

 I once knew a chicken who lived for ten and a half years.I was very upset when she died, but I think that's about as old as a chicken can get.