How We Make Blown Goose and Duck Eggs

Blown duck and goose eggs can be used to make beautifully decorated egg art. To see examples, see our post on BlownEgg Art.

How the eggs are emptied and cleaned for decorating can differ from person to person. An older method of blowing the eggs is to poke a hole in both ends of the egg, swirl a stick in it to break up the yolk, and literally blow into the egg in one end and the yolk and white goes out the other end - hence the term ‘blown’ egg.

We do not physically blow our duck and goose eggs, however, as we would have fainting employees every day if we did! 
 

We start with a device that helps us mark the exact center of the large end of the egg. We want the hole in the exact center so if the egg is hung from the hole, the egg hangs perfectly straight. The egg is then taken to a Dremel drill and using one of their 192 carving/engraving bits we drill the actual hole which measures 5/32 of an inch in diameter.

The drilled eggs are then placed hole down over short pieces of small copper tubing that are connected to an air compressor and a water source. Initially air is blown into the egg which forces the egg contents out the hole. After the insides are drained, water is then pushed through the copper tube to rinse out any remaining contents. Then we use a soap solution to clean the inside. Finally, we rinse out the soapy water with clean water and use a final blast of air to get all the water out of the egg. 
 

Goose eggs are measured after cleaning. A tape measure is wrapped around the length of the egg, not the width, to determine the size. The eggs are sold by this circumference measurement and range from 8“ to over 12“. A 10“ goose egg, for instance, measures anywhere from 10“ to almost 10.5“ in circumference. Duck eggs, on the other hand, are measured by their weight when they are washed by our automatic egg washer and grader when they enter the hatchery. The duck eggs come in Pee Wee, Small, Medium, Large and Jumbo sizes. As duck eggs are much larger than chicken eggs, our Small is equivalent to a Jumbo chicken egg.

After the egg contents have been removed and the inside of the egg has been cleaned and rinsed, the shell itself is carefully cleaned with a dilute solution of water and vinegar.

Once shiny and clean, the eggs are left to dry and then boxed and stored until a customer places an order for them. If blown and cleaned properly, an egg should never decay. For more information on the blown eggs we sell, please visit our BlownGoose and Duck Egg page on our website.

What Temperatures Kill In An Incubator?

We all know the ideal temperature for incubators range from about 98 to 100.3 depending on the stage of incubation.  But what happens if your incubator becomes too hot or too cold?  Of course each circumstance is different but I can tell you some of my experiences and maybe this will help you in case you have a problem in the future.

Low Temperature:
We remove some of our fertile duck eggs at 17 days of incubation and sell them as balut (a Filipino and Vietnamese delicacy).  Recently we set aside 160 large balut on Thursday for a customer that was to pick them up on Friday.  On Saturday we realized they were not going to be picked up.  I decided to put them back in the incubator but first I checked their shell temperature.  The surface temperature of each egg was between 71 and 73 degrees.  Remember, these eggs had been out of the incubator for 48 hours in flats in a case at room temperature.

We monitored those eggs and ten days later 75% of them hatched!  They were a day late but we still hatched 120 ducklings!  This was only 13% less than if they had not sat out for two days.

These eggs were old enough that they were putting off more heat than they required, so development was slowed but not stopped.  So if for some reason your incubator has a problem and cools down for a period of time, don't worry.  It probably will not adversely affect your hatch.

High Temperatures
High temperatures in an incubator are an entirely different matter.   Injury or death depends on how hot it gets and how long it is hot.  Hot temperatures for brief periods usually cause no problem.  But sustained higher temperatures allow the entire interior of the egg to become hot and that is when injury and death occurs.  And if it is an older embryo, it is generating heat and this makes overheating even quicker.

There are no black and white limits with overheating.  Years ago I lost all the eggs in an incubator when it was 105 degrees for six hours.  But on another occasion, I had no losses when the incubator was 102 for four hours.  An interior temperature of 103 almost guarantees death.

Just recently we had a machine that was supposed to be 98.7 gradually increase to 104 degrees over 3.5 hours.  When it was discovered, we cooled the eggs as described below and the resulting hatch was completely normal.  The eggs were 24 days old at the time.

What To Do When You Discover Your Hot Incubator
Immediately cool the eggs with water.  If you have lots of eggs, spray with a garden sprayer or hose.  If you have just a few eggs, dunk each egg in cool, not cold, water.  Blow air over the eggs to more quickly cool them.  Each time the egg dries, wet it again.  Remember that as you cool the eggs, the shell will cool faster than the interior - but it is the embryo in the interior that must be cooled.  Therefore, you want to cool the shell lower than the ideal temperature.  And as I described above, don't be afraid of cooling them too much as temperatures below ideal will not be a problem.

If you have an infrared thermometer, I would cool the shell to 80-85 degrees.  If you do not have a thermometer, hold it against your eye lid.  Once it feels slightly cool, put it back in the incubator and turn it on (assuming you have fixed the problem in your incubator!).

Don't Give Up On The Eggs
Once you stabilize the temperature, wait a day and then candle the eggs.  If they have died, you will know as there will be no movement and all blood veins will have disintegrated.  Only then should you throw away your eggs.  If you are not sure, leave the eggs in the incubator.  You have little to lose keeping them in the incubator.

What experiences do you have after finding incubators colder or hotter than they should be?

What Is So Special About A Constant Incubator Temperature?

Most of you have incubators that have several different ages of eggs in them.  And you have your incubator set to one constant temperature.  Right?  What I learned the other day is you want one constant temperature during incubation.  But not the incubator temperature - the shell temperature!

Last Friday we were visited by Jerry Garrison and Phillip Percy, technical advisors from Jamesway, the company that built our new Incubators.  Jerry told me they are learning that the shell temperature is the important temperature, not incubator temperature.   And the reason you want to know the shell temperature is that closely follows the temperature of the embryo which should be stable throughout incubation.

We have single stage incubators for our duck and goose eggs, which means all the eggs in that machine are set to hatch on the same day.  We start the incubator temperature at 100.3 and by the time they start hatching it is set at 98.2.  But he said if we measured the shell temperature, it should always read about 100.2!

Why does the shell temperature differ from the incubator temperature?  Initially the embryo is very small and not generating any measurable heat.  But the egg shell is cooler than the incubator because small amounts of moisture are evaporating from the shell which cools it - just as our sweat cools us.  This water loss is normal as an egg loses 13-14% of its weight during incubation.

However, as the embryo grows, it starts generating more and more heat.  Eventually it is producing so much heat that it's shell temperature can be two degrees warmer than the air in the incubator.  The egg is warming the surrounding air - not vice versa.

So how do you know the shell temperature of incubating eggs?  You can get a infrared thermometer.  You can get inexpensive one for only $60 but they do not measure in 1/10's of a degree.  To measure as accurately as necessary you need to spend several hundred dollars.

The best way to maintain a constant shell temperature is to have a single stage incubator (only one age of eggs in the incubator).   To have a shell temperature of 100.2, you need it to be 100.3 in the beginning and then gradually reduce it until it is about 98.2 when they start hatching.  For more information on single stage incubation, click this link and select the third article.

If you are used to setting every week, how do you switch to single stage incubation?  You would need at least two incubators and set eggs every two weeks.  Your first egg set of the spring would be in one incubator.  Ten to fourteen days later (10 days if you are setting chicken eggs, 14 for ducks) you set all your eggs in the second incubator.  By rotating your egg set from one incubator to the other, you have created two single stage incubators!  Just be sure the incubator is capable of sufficient ventilation to cool itself when it is full of older, heat producing embryos.

The biggest advantage of the multi-stage incubator is that it is easy.  The disadvantage is the embryos will be slightly cool early in the incubation and slightly warm late in incubation.

I found the idea of a constant embryo temperature fascinating - and how that varies from the incubator temperature.  Do any of you have experience measuring shell temperatures or using single stage incubation?