Even though many
people choose to cull two year old hens from their flock, chickens can actually live
up to 16 years.  The average natural life span is closer to five
or ten years, though, and is highly dependent on breed.  Hybrids
tend to live much shorter spans since they pour a lot of their energy
into that daily egg or into putting on weight as quickly as possible,
and one site reports that Cornish Crosses will live only two years even
under good conditions.



Another way to look at a
hen’s life span is based on the total number of eggs she can lay. 
Many people believe that a chicken can only lay 600 to 800 eggs before
she dies, so if she’s one of the breeds that pops out nearly an egg a
day, she may have laid just about all she’s going to lay by the time
she’s passed through two or three egg-laying seasons.  Hens who
produce fewer eggs per year may be able to lay eggs for more years
before kicking the bucket.



Our oldest hens are about to
celebrate their fourth birthdays, and I suspect 2011 may be their last
year on the farm.  Of the original twenty Golden Comets we got in
2007, two died of heat stroke their first year (the impetus for the Avian Aqua Miser), we gave twelve away
because we were awash in eggs, one was fatally injured by a previous
rooster, and two more have died of natural causes since then.  The
last three hens in that age bracket are wilely old birds, and I hope to
snag their genetics by mating them with our young rooster and raising
some chicks this spring.  And I won’t cull them from the flock
until they’ve slowed down their summer laying, so for all I know, they
may have another dozen years to go.

Choosing to cull a chicken from your flock is
seldom an easy decision, but without careful culling your flock will
end up full of non-productive birds.  Some chicken-keepers
simplify matters by starting a new batch of laying hens each year and
killing their two year old hens once the younger birds begin to lay,
while other people go to the other extreme and keep every chicken until
they die of old age.  I stick to a middle of the road approach,
but lean a bit more toward the latter method than I should if I wanted
the optimal laying flock.



In my experience, a few birds should always be
culled immediately.  A rooster which is aggressive toward its
keepers should always go in the pot.  On the other hand, if your
rooster overmates your hens, chances are the fault is yours — check
out my tips on the optimal
rooster to hen ratio and decide whether you can change your system
and keep this rooster.



A sick or injured
chicken should be separated from the flock for up to a week to allow
her time to heal without being picked on by her sisters.  If she’s
unable to regain full health, you’re going to either have to keep her
in isolation for the rest of her life (which is cruel to social
chickens) or cull the injured chicken.  Chickens naturally pick on
birds that aren’t quite up to par, and I believe that it’s kinder to
put a chicken out of her misery than to return her to the flock for
constant harassment.



Older hens who aren’t
laying much are a trickier topic.  Even though egg production
begins to decline after a chicken’s first year of laying, we find it
worthwhile to keep our best hens around for a few more years. 
During the summer, good egg layers will nearly match their younger
sisters, and we can afford to let them take the winters off in order to
keep their optimal genes and good foraging behavior in circulation
through our flock.



What if you think that one or two hens in your
flock aren’t pulling their weight but aren’t quite sure which ones they
are?  First, make sure that your flock’s not molting
— during the molt, chickens naturally stop laying, so you shouldn’t
make any hasty decisions on their future during this time period. 
If it’s spring or summer, though, you can test to see if individual
hens are slacking off by putting each one in a chicken tractor where
you can monitor her individual egg production for a week or two. 
Rotating your flock through the tractor will often be enough to pick
out which hen or hens are falling down on the job.  It’s worth
trying to perk your troubled chicken up with exra protein, calcium, and
greenery for a few more weeks before signing her death warrant —
again, the problem could be your fault and easily fixed.



My last piece of advice
is — once you’ve made the decision, don’t procrastinate.  We had
a loner chicken waiting for the guillotine for months, and every
morning I’ve spent time feeding her even though she wasn’t producing
any eggs.  It took us less than an hour to set up our
chicken-killing station and get it done, which will save me time and
lower our feed costs all winter.  Plus, it just feels good knowing
that every member of our flock has a use and is working hard.