Quote:

Originally Posted by

**Akrnaf2**
This is a translation of a post that I have written in a forum in Israel that I am one of its admins. I hope it will help thous that cano't see the development of the air cell in a very dark shell eggs:

Anyone who incubate eggs know that one of the most important parameters except the incubation temperature, is the humidity.

The accepted convention says that incubation eggs (in the first 19 days) should have humidity of 50% and during the hatching (days 19-21) humidity should move around the 75%.

I would like to say that such determinations are not absolute!

We must remember that moisture is the only means of bringing the egg weight loss necessary for the development of air cell. Chicken eggs have to lose 11-13 percent of their weight from day 1 to day 19 of incubation. This is the percentage that allows the creation of proper air cell and normal development! If the egg does not lose weight at the appropriate rate that the an air sack will develop properly, mean that the incubator humidity is too high and we need to reduce it! And if it losses weight that is higher than 11-13 percent and the air cell is greater than that needed, means that the humidity in an incubator is lower that what is needed, and we should raise it! The correct way to determine the correct incubation humidity present is to calculate the future weight loss of of the egg.

And the way to calculate this is:

You should weight the egg before entering it to the incubation. After the first 4 days ,in the first candling you weight it again. The gap weight (starting weight less weight on the fourth day), you divide the initial weight of the egg, the result should be multiplied by 100, that is the percentage of weight lost, percentage, for four days. Daily weight loss percentages can be known by dividing the result by 4.

To know the expected rate of weight loss of the entire incubation period you should multiplied the percentage of daily weight loss by 19. and this is the expected weight loss over the incubation. If it is between 11-13 percent humidity you are good, If it do not, you should correct the humidity levels!

for example:

If the initial egg weight is 56 grams

And after 4 days is 54.8 grams.

So: the ratio of weight lost in 4 days is:

0.0214 = (56 - 54.8):56

Multiple the result by 100

And This Is considered the weight loss percentages for 4 days:

0.0214 * 100 = 2.14%

2.14% are weight loss in 4 days. So to know the daily weight loss percentages is:

2.14% : 4 = 0.54%

Calculate the percentage of weight loss per incubation period (first 19 days):

0.54% * 19 = 10.3%

Originally Posted by

**Akrnaf2**
Only one thing more, you should know that the evaporating pace is dependent on the s/v of the eggs! Big eggs have little s/v so they less evaporating than small eggs that have a big s/v, in the same external humidity and temp.

Quote:

Thanks for posting.

That's exactly the way I do it. I can't see in most of the eggs anyway.

I don't even use a hygrometer since I threw them all away when they wouldn't stay calibrated.

I use graph paper and make a chart with starting weight and target weight and draw a straight line between the two. Periodic weighing should be points on the line. That way I don't have to do the calculations each time I weigh.

If they lose too much weight, I increase the humidity and vice versa.

I weigh individual eggs upon collection. Then if only setting a few, I'll have a graph for each egg. If I'm setting a lot. I usually weigh two or 3 dozen at a time. I still spot check individual eggs because occasionally one or two eggs will lose at a much different rate than the rest.

Quote:

This humidity Value of 10.3% is lower than the minimum of 11% percent required, it means that probably that humidity in the incubator was higher than necessary and you have to reduce it!

Only one thing more, you should know that the evaporating pace is dependent on the s/v of the eggs! Big eggs have little s/v so they less evaporating than small eggs that have a big s/v, in the same external humidity and temp.

Awesome! 'already have this in the article and made a xl file for helping

unprotectedfieldscanbeeditedwithCAUTIONforfunctions.xls 306k .xls file

WEIGHING EGGS

Chicken eggs need to lose 13% moisture over 21 days, NOT day 18 lockdown. Weigh all the eggs on the first day, before you put them in the incubator and weigh again days 10, 14 & 18. Several formulas can be used to determine the rate of weight loss or overall per cent weight loss and to correct the humidity if the values are off. For accuracy, a digital scale should be used which can weigh in grams. Don't forget to subtract the weight of the container holding the eggs from the total weight when calculating the average egg weight. If you use a rack to incubate your eggs it is best to weigh the entire rack instead of each egg to get an average. If you are incubating SHIPPED eggs upright in a carton you will also weigh the entire carton so that the eggs are not disturbed.

Some Explainations from cochins1088 on weighing Eggs!

Eggs should lose approximately 11% - 12% of their mass at 18^{th} day of incubation. To monitor mass loss, a person must keep track of an egg’s weight. Optimally eggs should be weighed right after they’re laid, but this isn’t always possible. When eggs are shipped, weigh them as you remove them from the package. Keep in mind that the eggs will lose some of their mass during storage. According to Aviagen, eggs lose about 0.5% of their masses per week in storage.

How to Calculate Mass Loss

First subtract the current weight of an egg from the original weight of the egg. This number will give you the weight loss. Then take the weight loss and divide it by the original weight of the egg. This will give you the fraction of weight that was loss. Lastly, multiply the fraction of weigh loss by 100. This will give you the percent of mass loss.

For example:

Original weight (50 g) - Current weight (45 g) = Weight lost (5 g)

Weight lost (5 g) divided by Original weight (50 g) = Fraction of weight lost (0.1)

Fraction of weight lost (0.1) multiplied by 100 = Percent of weight lost (10%)

For those of you who incubate large numbers of eggs, you can weigh the trays to find the average mass of each egg.

For example:

If a tray weigh of eggs initially weighs 700 grams and the empty tray weighs 200 grams, than the eggs must initially weigh 500 grams. If there are 10 eggs in the tray, then each egg weighs approximately 50 grams.

Let’s say that 2 eggs are removed because they were infertile.

After 18 days, your tray weighs 560 grams. If you subtract the weight of the tray (200 grams), than the eggs must weigh 360 grams. There are 8 eggs in the tray, so each egg weighs approximately 45 grams.

With this example, the eggs lost 10% of their mass by day 18.

**WHY **to MEASURE WEIGHT LOSS IN EGGS,

**MEASURING PROCEDURES (HOW TO), HOW TO CALCULATE, and HOW to interpret RESULTS **

http://www.aviagen.com/assets/Tech_Center/BB_Resources_Tools/AA_How_Tos/AAHowto1WaterLossEN13.pdf

For formulas used to determine the weight loss please refer to

Weight Loss Determinations:

http://www.falconryforum.co.uk/showthread.php?t=29983&langid=3

Note: Kitchen scales work great. The WeighMax Pocket Mini CD Digital Scale below works great if you weigh individual eggs. I pasted an egg carton cup firmly to hold the eggs. Be extremely careful not to tip your scale and crack your eggs!

Quote:

Originally Posted by

**ChickenCanoe**
Quote:

Originally Posted by

**Akrnaf2**
I would start earlier, day 4-5, to get an indication ASAP to have a big time margin to correct if needed!

SHIPPED EGG & Weighing DISCUSSION @Akrnaf2

HERE is my issue with the weigh eggs thing.....

When I weighed my own 7 day old eggs things are fine. Trouble is most people are incubating shipped eggs where the original weights are FAR FAR different than when we set our own. Number one issue being the way people pack everything in newspaper and cardboard without protecting the eggs from loosing weight. The ship leaving both ends of the bubble wrap open most times because that is WHAT is suggested to them. It is known through research that we can store eggs in plastic bags to help prevent the loss and the ph changes in the albumen. Anyways, if we are weighing for such accuracy how can we do so with such unknowns on the eggs themselves? Most times we set our own eggs are basically a A grade or AA grade egg. When we get them shipped they are most times well Beyond a B grade egg. If you look at the images below, that is already quite weight loss.

My issue is honestly telling people to weigh eggs on this unknown, I always try to tell them the perfect methods and back up everything I tell someone. This weighing of shipped eggs I just cant ever suggest to someone, esp a new hatcher....... I know how easy it is to say "it worked for me" but that would be just heresay..... am I making any sense in all that blabber above? I pray paddler you can seriously open my mind up here, as it is its not.

Edited by Sally Sunshine - 1/21/16 at 9:11pm