The internet is chock full of
information about hatching chicken eggs…but it’s all the same
information repeated over and over on different websites.  Yes,
the basic humidity, days to hatch, and temperature information is
important, but what if you want to delve deeper into learning about
incubation?  Am I really the only nervous chicken mother who wants
to know what percentage of chicks get out of the shell on day 21 during
an optimal hatch and when it’s kosher to help chicks?  That’s when
you give up on websites and move to books.



Most of the modern books I’ve
browsed present the same information that can be found on the web, with
my favorite so far being the “hatchery and incubation” chapter in Day Range
Poultry
by Andy Lee and Patricia Foreman.  You can tell that the duo have
had quite a bit of hands-on experience, and they present more than
the basics, although still only enough to whet my appetite.  Storey’s
Guide to Raising Chickens
by Gail Damerow also has a long chapter on incubation, but the text
seems to be heavy on operation of the actual incubator and on chick
identification methods and light on the biological information I
crave.  Despite the name, Success
With Baby Chicks
by Robert Plamondon  starts when the box of chicks arrives from
the hatchery and doesn’t consider incubation at all.  Finally, The
Incubation Book
by A.F. Anderson-Brown looks interesting, but I haven’t been able to
get my hands on a copy yet.



Eventually, it occurred to me
that chickens have been hatching for a very long time, and I should
take a look at old books in the public domain.  Two of the ones I
rustled up were worthless, but I stumbled across a real gem in the 105
year old Incubation:
Natural and Artificial, by J.H. Sutcliffe. 
This out of print book is available as a free ebook, and you can
download the pdf version by clicking on this link.  (Alternatively, visit
OpenLibrary to see other file
formats.)  So far, I’ve only dipped into the hatching chapter
(which already answered half of my most pressing questions), but I plan
to read the book more carefully later, especially the introduction that
discusses how Egyptians have artificially incubated eggs for thousands
of years.



I’m still looking for
answers, though, and could use some more book recommendations. 
Which books have you found eased your mind during incubation?

Dry
incubation means exactly what it sounds like — you incubate your
chicken eggs without adding any water to the wells of the
incubator.  The goal is to get your eggs to lose 13% of their
weight by day 18 so that the chicks will have large enough air pockets
to hatch correctly.  Although this technique flies in the face of
the instructions that come with most incubators, many home hatchers
swear by dry incubation and say they get better results that way.

For everyone who loves
dry incubation, there is a naysayer for whom dry incubation didn’t
work, and here’s why — air temperature and humidity have a huge
impact on humidity in your incubator.  For my late May/early June
incubator run, I put in absolutely no water, and the humidity in my
incubator was still so high that I was only able to get the eggs to
lose 11% of their weight.  On the other hand, people who live in
desert climates can’t use dry incubation techniques or their eggs lose
far too much moisture.

Some dry hatchers not
only leave water out of their incubator, they also use a dehumidifier
in the room, which is what I would probably have to do to get 13%
weight loss from our eggs during our humid summers.  At the other
extreme, folks in dry climates sometimes add humidifiers to their rooms
to increase the ambient humidity, although it’s usually easier to
increase humidity just within the incubator by adding water to the
wells.  Regardless of how you get there, the incubator’s goal
humidity is 30% to 40% if you’re a dry hatcher or 40% to 50%
if you’re a conventional hatcher.  (This is all for days 1 through
18 — see how
and why to raise the humidity during hatch here.)

I’ve posted before about how egg
weight loss during incubation is the real test of whether your
incubator’s humidity levels are correct.  I know the formulas in
that post look a bit daunting — that’s why I made a spreadsheet for
this hatch that does the calculations for me.  You can download
my spreadsheet and
use it during your own incubation run, whether wet or dry.  I hope
it helps you get more living chicks as a result!