Sex Determination of Day-Old Chicks

Canfield, T. H.

doi:10.3382/ps.0200327

Cited by 8 publications

(3 citation statements)

References 1 publication

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“…The most important point to note about the pictures shown in Figure 1 is that they were initially created by Canfield (1940Canfield ( , 1941 to depict rare and difficult types. Their high level of difficulty provided us with an opportunity to obtain sufficient errors from the experts to correlate performance over the various pictures with the performance of subjects who received instructions in the course of our experiment, To our knowledge these are the only pictures of variations in chick genitalia.…”

Section: Picturesmentioning

confidence: 99%

“…Not a single sexer, including one who went through a special school devoted to sexing, reported ever seeing pictures of chick genitalia. Canfield (1941) reported the frequency of the various types in a sample of 10,000 chicks from "random commercial flocks." Male Types a and b were reported as constituting 64.32% of the sample; c, 7.85%; d and d', 0.58%; e and f, 20.53%; and h, 3.41%.…”

Section: Picturesmentioning

confidence: 99%

“…Gibson's Principles of Perceptual Learning and Development (1969). Professor Gibson had reproduced a figure from Canfield (1941) that showed the genital eminences of pullets and cockerels (Figure 1). Despite a considerable initial effort We express our sincere appreciation to the professional sexers, Heimer Carlson, Margaret Ashton, Emily Faria, Gladys Rose, Min Sagimori, Jack Scott, and Mervin Tells, for their willing participation in this investigation.…”

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confidence: 99%

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Sexing day-old chicks: A case study and expert systems analysis of a difficult perceptual-learning task.

Biederman

Shiffrar²

1987

Journal of Experimental Psychology: Learning, Memory, and Cogni

270

188

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The sexing of day-old chicks has been regarded as an extraordinarily difficult perceptual task requiring years of extensive practice for its mastery. Experts can sex chicks at over 98% accuracy at a rate of 1,000 chicks per hour spending less than a half second viewing the cloacal region. Naive subjects were shown 18 pictures of cloacal regions of male and female chicks (in random appearing arrangement) and asked to judge the sex of each chick. The pictures included a number of rare and difficult configurations. The subjects were then instructed as to the location of a critical cloacal structure for which a simple contrast in shape (convex vs. concave or flat) could serve as an indicant of sex. When the subjects judged the pictures again (in a different order), accuracy increased from slightly above chance to a level comparable to that achieved by a sample of experts. The correlation (over items) between the naive subjects and the experts before instruction was .21; after instruction, .82. The instructions were based on an interview and observation of an expert who had spent 50 years sexing 55 million chicks. Much of the reported difficulty in developing perceptual expertise in this task may stem from the need to classify extremely rare configurations in which the convexity of the structure is not apparent. The rate of learning of these instances could be greatly increased through the use of simple instructions that specified the location of diagnostic contour contrasts. A parallel is drawn between learning to sex chicks and learning to classify tanks as friend or foe.

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Section: Picturesmentioning

confidence: 99%

Section: Picturesmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Sexing day-old chicks: A case study and expert systems analysis of a difficult perceptual-learning task.

Biederman

Shiffrar²

1987

Journal of Experimental Psychology: Learning, Memory, and Cogni

270

188

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Degree of sex reversal as related to plasma steroid levels in genetic female chickens (Gallus domesticus) treated with fadrozole

Vaillant

Guemene²,

Dorizzi

et al. 2003

Molecular Reproduction Devel

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The objectives of this work were to determine whether or not plasma levels of testosterone and estradiol reflect the various grades of sex reversal in genetic female chickens treated with Fadrozole (CGS 16949 A), a nonsteroidal aromatase inhibitor, and whether gonadal aromatase activity and plasma levels of testosterone and estradiol in treated females can or not be modified by post-hatch treatments with Fadrozole or Fadrozole + testosterone. Eggs were injected with 1 mg Fadrozole on day 4 of incubation. In females having developed sex-reversed gonads, endocrine parameters (estradiol and testosterone) at and after 13 weeks of age were indicative of the degree of sex reversal, with, for example, sex-reversed females with two testes having the highest levels of testosterone and the lowest levels of estradiol. Among these females, eight (from a total of 13) produced ejaculates with scarce and abnormal spermatozoa. Some motility was observable in the ejaculates from five of them. None of the post-hatch treatments had a significant effect on plasma levels of testosterone or estradiol (measured at 3-week intervals from week 4 to week 28 post-hatch) or on gonadal aromatase activity (measured at 12 and 28 weeks). In conclusion, these results indicate that plasma levels of testosterone and estradiol at and after 13 weeks of age are valuable indicators of the degree of sex reversal in female chickens treated with Fadrozole prior to gonadal sex differentiation. In pre-cited conditions, post-natal treatments with either Fadrozole or Fadrozole + testosterone had no apparent effect on the degree of sex reversal in these birds. Finally, the occurrence of ejaculates with motile although scarce and abnormal spermatozoa, revealed that epididymes and ducti deferens can develop and become functional in sex-reversed female chickens.

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