Canadian Poultry Magazine

Electronic egg grading

By A. S. Kyle Hatchery Inspection Service Dominion Department of Agriculture   

Features 100th anniversary Equipment Poultry Equipment Technology Poultry Production Production

September 1949

The past few years has brought about many changes, and most notable, is the trend towards quality eggs and the possible increase in the total hatch of chicks from high quality eggs.

Three years ago a group of hatcherymen in the Fraser Valley started to candle all eggs before setting, and to this, the increased hatch for the Province is in great part due. The total hatch on all eggs set climbed from 63.4% to 69.8% of saleable chicks.

With the quality factor in mind the writer had high hopes when Dr. A. L. Romanoff of Cornell announced the inventing of an electronic Egg Candling Machine, as this would remove the human factor in candling. This was short lived as it was not possible to secure a machine.

At this point Mr. T. Gascoigne of Cloverdale, British Columbia let it be known that he was working on a machine and the task of ironing out the difficult points started.

Early this year the Bureau of Animal Industry U.S. Dept. of Agriculture released a Farm Paper letter on Pre-Incubation for Higher Hatches and we give it as it appears in Poultry Digest.

“A new method of handling hatching eggs has been found whereby infertile eggs can be detected and removed by candling on the farm where they are produced before being sent to the hatchery. This method, according to the Bureau of Animal Industry, USDA, makes it possible for those producing hatching eggs to guarantee almost 100% fertile eggs to the hatchery. To effect the extra cost of pre-incubating and candling, it would be to the interest of the hatcheryman to pay the flock-owner a premium for such eggs.”

“The method consists of incubating hen eggs for 16 to 18 hours at 100 degrees F., then removing them, and with the aid of a candler separating the fertile and infertile eggs. The embryo a this state of development is about the size of a dime, and appears before the candler as a small bubble floating on the surface of the yolk.”

“After the fertile and infertile eggs are segregated, the fertile eggs to be sold for hatching purposes are place in open wire trays in a cooler for two hours at 50-95 degrees F. This is done to check further embryonic development before the eggs are shipped. The eggs are then packed in pre-cooled cases and shipped to the customer.”

“Test shipments of pre-incubated eggs as well as unincubated eggs have been sent on round trips from Beltsville, Md., to Hartford, Conn., St. Louis, Mo., and Des Moines, Iowa. On return, the eggs of each shipment were replaced in the incubator and allowed to hatch. It was found that the pre-incubated eggs, after being shipped to these points and being en route from 50 to 96 hours, hatched as well as unincubated eggs of the same quality which served as controls and which were shipped along with the pre-incubated eggs in the same cases. Slightly over 80% of the pre-incubated fertile eggs shipped hatched and 18 hours earlier than the eggs used as the controls.”

“These studies have now been extended to include turkey eggs. Some 1,500 Beltsville Small White turkey eggs have been pre-incubated and shipped following, in general, the same procedure as that used for chicken eggs. The turkey eggs, due to slower development of embryos, are incubated for 24 hours before being candled. They are then cooled for tow hours at 50-55 degrees F.”

“Although it is more difficult to see the turkey embryos than chicken embryos, eggs with near perfect fertility can be sent if the shipper is willing to withhold all “doubtfuls.” These “doubtfuls” can be incubated by the producer in order to salvage any mistakes. With a more powerful candler many of these “doubtfuls” could probably be eliminated.

“Cases of pre-incubated turkey eggs have been shipped all the way across the country, and the hatchability of fertile eggs of the pre-incubated group was as good as that of the unincubated eggs used as controls.”

“Getting rid of infertile eggs at the farm before the eggs are shipped has many advantages. It is estimated that on the average 15% of all hatching eggs are infertile. Removal of these eggs at 18 hours incubation thus saves incubator space as well as reduces cost of shipping and handling. Since almost all the pre-incubated eggs shipped would be fertile, the hatcheryman could be assured of a near-perfect fertility and consequently a higher percentage hatch of total eggs set.”

This was brought to the attention of Mr. G. R. Wilson District Inspector of Poultry Services of B.C. who thought some test work would be in order, so with the co-operation of several Hatcheries, Mr. Gascoigne, and Mr. Pat Cain, Head of the Egg Grading staff, a number of hatches were run through, a few of which are given as a progress report.

5 cases – at 17 hrs. incubation
Infertile 21.4%
Fertile A or No. 1 – 656 eggs, 505 cks. = 77 %
Fertile B or No. 2 – 672 eggs, 405 cks. = 60.3%
Not candled – 236 eggs, 142 cks. = 60.1%
2 trays marked Top Grade A hatched 81%
1 tray marked Low Grade B hatched 54%

On a set candle for quality only before setting.

No. 1 or A’s, 1878 eggs, 1412 chicks = 75.2%
No. 2 or B’s, 537 eggs, 316 chicks = 58.2 %

On a set with Incubation for 18 hours:

Infertile 19.2%
Fertile A’s or No. 1, 1044 eggs, 797 chicks = 76.5%
Fertile B’s or No. 2, 304 eggs, 176 chicks = 57.8%

In this set a very interesting point appears – In the A’s – 82 eggs were removed at the 18th day transfer and 165 were left on the trays.

On the B’s – 81 eggs removed at the 18th day and 47 left on the trays.

This gives a 7.8% death rate up to transfer time on A quality while B quality is 26.5% and the left on trays is the same in both i.e. – 15.4%.

A top grade A tray hatched 86.7%

A low grade B tray hatched 50.8%

From these hatches one might reason that candling at the incubator would solve a lot of problems, but candling should be done at the nest. The question is, will a chick hatched from a low quality egg, in turn, lay a low quality egg, if so, why should the breeder ask the hatchery operator to correct mistakes made in the breeding program.

To ship fertile eggs only, would require more study, but it is quite possible to put the program into operation on a breeding farm or hatchery. Incubation must be stopped at the 18th hour by quick cooling if the eggs are to be shipped. And it also would be wise to do so even if the eggs are going back into the machine so as to insure hatch time.

Infertile eggs show no change as the 18th hour period. On the electronic machine they show a drop of 2 points while a fertile one drops 8 to 10 points.

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