Author: Anna & Mark

Weighing
your eggs is the best way to make sure you’ve got the
humidity inside
your incubator
right.  I figured some of you might find the idea
daunting, so I’ll take you through it step by step.



First, you want to find
the weight of your eggs at the time you put
them in the incubator.  There’s no need to weigh one egg at a time
— just put all of the eggs on a scales at once.  If you’re lucky
and your tray of eggs can be lifted straight out of the incubator (like
in our new Brinsea
Octagon 20), you can
put the tray and eggs on the
scales together.  Then take the eggs out of the tray and weigh the
tray alone.  The weight of the eggs without the tray can be
calculated using the following simple formula:

Our eggs and tray
weighed 59.8 ounces at the beginning of our
incubation period and the tray alone weighed 7.3 ounces, so the eggs
weighed:

The next step is to
figure out how much I want the eggs to weigh at the
end of the incubation period.  We’re aiming for a 13% weight loss,
so:

For our eggs, that is:

It’s also useful to know
what our daily weight loss goal is:

Our eggs need to lose:

(For those of you who
ran away from algebra, be sure to do the subtraction before the
division in the equation above.)



Now I’m ready to find
out if my eggs are on track with their goal
weight loss on a certain day.  After two full days of incubation,
I weighed my eggs and tray again, subtracted out the weight of the
tray, and got a new weight of 51.8 ounces.  Did I have the
humidity set right?



First, I calculate the
goal weight loss for the day:

For my eggs:

Next, I figure how much
the eggs should weigh now:

For my eggs:

If
you remember, my eggs weighed 51.8 ounces on day 2, so if anything
they’ve lost just a hair too much weight.  I had let the
incubator’s percent humidity drop down into the high 30s that morning
since it ran in the low 50s the first day, but it looks like I need to
refill the well or close the vent.



I hope this math doesn’t
look daunting!  I promise, it’s simple
arithmetic, and weighing your eggs every two or three days during
incubation should increase your hatch rates.

We decided to increase our
chances of success for our second round of incubation by upgrading to a
Brinsea Octagon 20 Advance Incubator.  I don’t really blame our hatching
problems on the Brinsea
Mini Advance Incubator,
but I do think that the larger model makes sense for our more difficult
incubation environment.  Here are the features that sold me on
upgrading:

• Larger capacity — After
  talking to several folks and reading lots of accounts online, I’m
  coming to realize that beginning chick-keepers should expect to hatch
  only a small percentage of the eggs they place in their
  incubator.  While we can work on improving our hatch rate, it also
  makes sense to hedge our bets by starting off with more eggs.  The
  Octagon 20 holds 24 hen eggs (fewer if you’re hatching all jumbo-sized
  eggs), which I hope will give us at least seven living chicks.
• Humidity readout and vent
  — In addition to tracking the temperature, the Octagon 20 gives a
  digital readout of the current humidity in the incubator.  There’s
  also a vent that you can open or close to help get the humidity into
  the range you’re looking for.  I’ll talk more about humidity in a
  later post, but I think that incorrect humidity in the incubator was
  one of the major causes of our low hatch rate the first time around.
• Less noisy — The eggs
  in the Octagon 20 are constantly being slowly rotated, so there’s no
  sudden beeping and then whirring as the eggs are turned.  This
  isn’t really important, but it’s nice not to have an alarm go off every
  45 minutes! 

That said, there are a
few disadvantages to the Octagon 20 compared to the Mini incubator:

• Larger size — Of
  course, it takes more room to fit 24 eggs compared to 7 eggs, but the
  way the egg-turner rotates the whole incubator from side to side means
  that the unit can’t sit close to a wall.
• A bit more setup — You
  have to assemble the egg-turner and take off a plastic plate to install
  the incubator’s power cord.  This isn’t really all that tough, but
  it will take you about half an hour with a Phillips screwdriver.
• No auto shutoff of the turning
  motor — The Mini incubator had a feature where it would
  automatically shut off the egg turning motor two days before
  hatch.  The egg-turner for the Octagon 20 is a separate unit with
  a separate power cord, so you have to shut the turner off manually when
  the time comes.  On the other hand, you need to increase the
  humidity in either incubator at the same time the egg turning stops, so
  there’s not a huge benefit to having the egg turner shut off
  automatically.  Plus, with the incubator and the egg-turner being
  completely separate for the Octagon 20, if one fails, you can just
  replace that part instead of your whole unit.

I also had a minor
problem that I hope none of you run into — I assembled the egg-turner
and it was missing a piece.  After second-guessing myself for a
while, I called Brinsea and they sent me out a replacement piece at no
cost, but the delay (just two working days, plus the weekend) meant the
hatching eggs I’d ordered online had to sit around while I waited on
the part.  The delay might affect our first hatch in the new
incubator, but is already water under the bridge.



The Brinsea Octagon 20
incubator is costly, at $300, but I’m hoping the extra money will be
worth it.  We’re going to have to hatch a lot of chicks to make
this incubator pay for itself….