Feed conversion rate with unlimited feed

I was disappointed by the feed
conversion rate of
our first round of 2012 broilers.  I felt like I did everything
right — providing higher quality pasture and feed than ever before, and even carrying
jars of cicadas to the chicks now and then.  But the
feed to meat ratio was a disappointing 5.6, worse than 75% of last
year’s efforts.  What happened?



I have several
hypotheses, one being that our new method of providing unlimited
storebought feed tempted the broilers to sit around the trough rather
than foraging.  (The chickens did seem to be foraging a lot, but
they clearly ate more storebought feed too.)  Granted, this year’s
broilers also grew a lot bigger than ever before, as you can see in the
first graph in this post — that blue blob nearly poking off the top of the
chart is the average weight of a 12 week old Black Australorp cockerel
in 2012, compared to the weights of Black Australorp, Cuckoo Marans,
and Light Sussex cockerels last year.



In a way, it’s worth
giving the chickens extra feed if you end up with larger broilers,
because there’s less butchering involved per pound of meat that
way.  It was also handy to be able to slide our three keepers (two
pullets and a cockerel) into the laying flock without the newcomers
being so small they were immediately beaten up.  And I had fewer
hard decisions to make since my chores simply consisted of topping off
the feeder so it was always full.  On the other hand, it’s
disappointing to still be feeding nearly twice the industry standard
per pound of meat. 



All of that said, I’m not
entirely sure that the unlimited feed was the cause of the lower feed
conversion rate this time around.  On a whim, I took a look at how
the proportion of male to female birds in the flock affected the feed
to meat ratio.  Although there’s not nearly enough data to come to
any conclusions, there is an interesting trend toward more males in the
flock meaning the birds eat a lot more per pound of meat they
produce.  Maybe those boy birds spend so much energy posturing
that they mess up my feed conversion rate?



I’m going to go ahead
and finish raising the second round of 2012 broilers with unlimited
feed this summer and will crunch some more numbers before deciding on a
game plan for our fall batch.