Candling eggs at day

When the time came to put our first eggs in
the incubator in February, something was telling me to add a few
extra.  Even though I can easily fit 24 full-size chicken eggs in
the Octagon
20 during the majority of incubation, the name suggests how many
can easily lie flat for hatching — 20 (or, if I’m careful, 21 or
22).  But I knew my hens were older than I’d like and had yet to
enjoy any spring greenery, so I filled the incubator up with 24 eggs.



The question became —
what would I do when it came time to hatch?  In the past, I
haven’t candled eggs because the heat from the light (and the oils from
my hands) can sometimes kill sensitive embryos, and I had no reason to
risk it.  But with too many eggs to lie flat, I decided to candle
on day 17 and pull out the obviously dead eggs. 



Sure enough, it was easy even with my
brown-shelled eggs to tell the difference between yolkers
and developed embryos.  The former allowed the light to shine
clear through everywhere, while the latter were opaque except for the
large air pocket near the top of the egg.  I even thought I could
tell the difference by feel — the yolkers were a bit lighter and more
fragile, while the living eggs were solid to my touch.  (I’m sorry
about the terrible photos — I’ve yet to learn to take good pictures
in very low light.)



And it turns out I’m
glad I threw in the extra eggs because my percent viability is quite
low this time around — only 70% based on candling data.  For the
sake of comparison, this first hatch always has lower viability than
later in the year, but when our hens were only a year old (in February
2012), their eggs had 81% viability (which rose to 95% for the early
April hatch).  It looks like having older hens is a problem in the
hatching arena as well as when looking for winter
eggs.