Canadian Poultry Magazine

Sexing Baby Chicks

By Prof. E. A. Lloyd   

Features 100th anniversary Technology Poultry Research Research

September 1933

There is no more interesting chapter in the history of the rise of the poultry industry than the sensational progress made by the people of Japan. The records show that they accomplished more over there in the five-year period 1925-1930 than we have in this century to date. Of course, the alert Japanese learned much from us when in 1927 and 1928 they came over to inspect and study the methods that were responsible for the world’s record stock of British Columbia and the Pacific States to the south. Encouraged and assisted by a sympathetic and progressive government with a real policy of improvement, they were not slow to secure the very best of the high record bloodlines of this continent. They accomplished this because they were willing to pay a good price for stock. Through the government farms and departments of agriculture and education in Japan this blood was multiplied and distributed to the farmers on such a comprehensive scale as to literally transform the poultry keeping from and insignificant sideline in farming into one of the most important branches of agriculture.

Figures from official records indicate an increase of 12 million head of high producing poultry in the country from 1927 to 1932. Egg production itself was raised from an average of 107.2 eggs to 122.8 in the same period. This the highest average secured in any country in the world. Higher averages are obtained in some districts but not over a nation as a whole. This is all the more remarkable when it is considered that the poultry population of Japan still includes a considerable proportion of the native breeds like the Nagoya and other less productive ones. Such production is pretty certain proof of the efficiency of the methods practiced in Japan. As a matter of fact there appears little doubt that these thorough going people have learned practically all that Occidentals had to teach them and “then some”.  Ample evidence now exists to show that in ne important new art the Japanese are three years ahead of the poultrymen in this country. This discovery is the determination of the sex of baby chicks by differences in the rudimentary copulative organs, or particularly the cloaca.

The Japanese got into the same trouble as our poultrymen with regard to surplus Leghorn broilers. Conditions in Japan were ever worse in this respect than in this country in 1929. There was practically no market over there for the tremendous numbers of these young cockerels produced through the rapid increase of the Leghorn breed in connection with the government’s big ten year program for increased production. Japanese scientists came to the rescue as they perfected their technique in sex determination. As far back as 1925 Dr. Masui of the Veterinary Division of the University of Tokio published a report of certain differences that he discovered in male and female chicks. When more advanced work was reported in a paper on “The Rudimentary Copulatory Organs of the Male Domestic Fowl and the Difference of the Sexes of Chickens” world wide interest was created in the important discovery. It was not considered to be feasible, however, from a commercial standpoint and also because of the time required to examine the chicks and the danger of injuring the young bird in the process.


It was not known by Dr. Masui or his co-workers in the early stages that chick sexing could be made practical for hatcheries or poultrymen. However, through the indomitable application of such practical pioneers as Kojima the practice was found to be commercially feasible. By intensive study of Dr. Masui’s method and the examination of the copulative organs of older chicks of 60 days of age he became familiar with the differences in the sexes. By comparing the organs of younger 30 days old and still younger chicks Kojima gradually improved his technique and familiarity with the organs and their differences to a point where he could distinguish the sexes at a day old. He also became able, through continued practice over a six months period during which he handled and examined thousands of chicks of different ages to make the examinations and decisions quickly.

Many others, like Sakajiyama have followed the example set by Kojima and have become practical teachers of Dr. Masui’s method of chick sexing. Meanwhile, Dr. Masui and Dr. Hashimoto have carried on their research on differences in different breeds and strains of chicks and other phases. The most recent findings are embodied in a book, which is now in the press. The previous classifications showing the different types of male and female chicks according to the presence or absence of genital eminence in the cloaca, as described in the Japanese textbook, are presented for students in the New Edition in the English translation.

Introduction of Chick Sexing into America

Considerable skepticism existed in England and on this continent regarding the commercial feasibility of chick sexing until recently when the Japanese expert Yogo gave his practical demonstrations. In Japan, the work, which has been developing ever since Kojima had such success in 1929-1930, is now carefully regulated for the most part by important organizations. The chief of these is the Japan Sex Propagate Association which consists of important scientists and officials in Japan, and which has received strong support from the Japan Poultry Journal. Mr. Takahashi, the owner and publisher of the Journal and an important teacher and investigator in his country, is president of the association, and Mr. Yamaguch, who is so well known in this country, and who is associate editor of the journal, is a director. The sexing experts themselves make up the principal rank and file membership in this professional organization.

Chick sexing in Japan is on a well organized educational and professional basis. Training schools have been conducted there for years in important poultry and hatchery centres. Students train for diplomas of third, second and first class Standards. Beginning with Thirds they gradually work up to the higher efficiency of speed and accuracy. A good many fail to qualify but already there are over 100 experts holding First Class Certificates in Japan. These men and women (there are 30 duly qualified young women experts in Japan) have shown in examinations that they can sex chicks at the minimum rate of 100 Leghorn chicks in 30 minutes, and with an accuracy of over 92 per cent. Most of them exceed these marks, especially after practice. The hatcheries employing such experts may safely guarantee that the sex of the chicks sold as pullets will be 90 per cent correct.

Although chick sexing was bound to be shown in this country soon, it was fortunate that the progressive Chick Sexing Propagate Association donated as a prize to the Grand Champion chick sexer of Japan a free trip to America. The Central Contests are held every year in Japan to stimulate competition and create interest in the outlying districts where the preliminary contests are held. Under the management and direction of Mr. Yamaguch, as is so well known now, demonstrations were arranged for and held this last spring at the University of B.C., Oregon Agricultural College, University of California and many hatcheries in different centres on the Pacific coast.

Every practical poultryman who does not cater to a special meat market knows what a nuisance the young cockerels are. The extra equipment, heat, space, labor and feed required just to rear to the age where sex can be detected, or they are fit to be “shot” into the market makes if a very expensive proposition. The expense appears to be superfluous, too.

If the cockerels could be marketed at a fair price when they were ready the trouble would be worth while. Even then their very presence would militate against the welfare of the pullets. So few commercial poultrymen, especially egg producers, make anything out of broilers that the more completely and the sooner they can be removed from the flocks the better.

It is from the standpoint of disease and the added menace brought about by brooding and rearing two chickens where only one is needed or ought to be that the greatest advantage would appear to accrue from chick sexing. The evils of overcrowding, in its stunting effects on birds, the unfair chance that the pullets have in competition with the more vigorous cockerels for feed; the feather eating, cannibalism, piling up; greater danger of infection from B.W.D., Coccidiosis, worms and paralysis and many more sanitary conditions or the absolute reduction of numbers as a safeguard. Chick sexing, which permits the egg producer to purchase just what he wants, viz., pullet chicks, looms up as a very useful aid in management problems and fighting the disease menace.

A New Profession

Boys and girls between the ages of 18 and 24, according to experience in Japan, will be attracted into this new and lucrative profession.  A little calculation will show their earning possibilities with fees at one cent a chick, and experts capable of sexing from 3000 to 5000 a day.

While these laboratory demonstrations were eminently successful in showing the extreme accuracy and speed with which chick sexing could be done by a first class expert of Yogo’s caliber, the practical work done for hatcheries was still more convincing. The star example was at the Bolivar Hatcheries where 25,000 chicks were sexed by Yogo in four days. A check of these birds at 5 and 6 weeks revealed only 39 cockerel chicks out of one large lot of 11,800 pullets or an error of less than one third of 1 per cent or an accuracy of 99.7 per cent, which is incredibly high. In the case of the cockerels the error was less than 1 per cent. It is reported that one poultryman who purchased 2000 sexed cockerel chicks and who expected to do well on the deal wasn’t so enthusiastic about it when he finally counted all of the pullets, which he could find.

In one lot of 500 sexed cockerels kept and fed by the Washington Co-operative Hatchery at Bellingham, one lone pullet was discovered later. In answer to a questionnaire sent out by the Co-op. to six of its members who had purchased sexed pullet chicks (2850 in number) the losses in brooding were found to be very light. The customers were well satisfied with the chicks and the majority were enthusiastic about chick sexing, promising to purchase nothing but sexed pullet chicks next season if they were available.

A very successful demonstration was given at the International Baby Chick Convention at Grand Rapids, Michigan, on August 8th, last, before over 1000 commercial poultrymen of U.S. and Canada. Before this assembly Yogo sexed 100 chicks with 100 per cent accuracy and on the speed test he sexed 200 chicks in 13 minutes and 27 seconds. A profound impression was created in the minds of these progressive hatcherymen, and a good many of whom turned out more than a million chicks in a year and who are appreciative of the importance of such a revolutionary practice. It was impossible to satisfy the demand or the demonstration and reservations were made by the hatcherymen for all available experts for the coming season.

Service to the Industry

It is not necessary to dwell upon the surplus broiler problem at this time. The writer has found it to be even more serious in other parts of this continent than in British Columbia. Poultrymen everywhere have sought to be relieved of it for years. Breeding sex-linked varieties has in some places been adopted to enable the detection and separation of the male from the female as baby chicks. This practice has attained considerable vogue in England and in the New England States. It does not meet the situation, however, on a large scale and leaves the White Leghorn entirely out of its sphere.

While records as high as 8,000 to 10,000 chicks have been made by experts in Japan, a good commercial average would be 4,000 to 5,000 chicks in an eight hour day. The work requires concentrated scrutiny of the eyes and exacting technique of the hands so that excessive speed is hard on the operator and does not make for the highest accuracy. In a hatching season approximately 100 days at least 300,000 could be handled by one expert.

An important part of the technique is the way in which the chick is held. The chick should be held firmly but softly so that the fingers and hand may be coordinated as light pressure is applied to the abdomen of the chick and the cloaca inverted and its folds exposed. The genital eminence of the male can be seen as a whitish projection when the vent has been properly opened, whereas in the female the folds and membrane do not show such a raised organ. Since the vent is very small and folds smaller very sharp eyes and strong eyesight are necessary. Whereas young people of from 18 to 24 years generally have the keenest eyesight and have the best chances of success in learning the art, it was really older men who perfected the art in Japan. Anyone with keen senses of touch and eyesight may become proficient. In any case it requires much practice, the use of many chicks and continuous reference to the text book to attain efficiency in separating the sexes.

Chick sexing has made its debut in this country and proves its worth at once. Henceforth it will be possible through its adoption by hatcherymen to supply poultrymen with the pullet or cockerel chicks as required. Poultrymen will produce better pullets at lower cost even when they pay twice as much for pullet chicks as for mixed chicks. The destruction of many young broilers will relieve the broiler market and permit of better prices for all market chickens. Broiler specialists will supply the market with chickens of better quality. Everyone concerned will benefit from the adoption of chick sexing, and work with good remuneration will be provided for many of our Canadian young men and women.  Millions of extra chicks will be required too for the schools. It all looks like good business for the poultry industry.

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