(Note – Pekins are referred to as Cochins in this article)

The ABA Standard defines brassiness as “Yellow metallic tinge found mostly on white and part-white varieties in the hackle, back, saddle and wings.” The APA Standard adds “…a serious defect…may be hereditary or affected by exposure to sun rays.” Ralph Sturgeon, in his excellent book “Start Where You Are With What You Have” indicates “environment and feed are often hailed as determinants of brassiness…students of heredity, however, scoff at such claims.” He further states “…we are on safer ground if we treat defects discovered in white colouration as a function of heredity.”

The apparent cause of brassiness is a gene for red colour. It is believed that direct sunlight “bleaches” this subdued red colour in white birds, and causes the hue we commonly call “brassy.” The STA-White characteristic in white chickens can be described as entirely free of any factors which contaminate or modify the white colorization expected in show stock.

The STA-WHITE colorization is not due to the presence of a new factor but the absence of an old one – that troublesome gene for red. Simply stated, the offspring gene ha been bred out of a specific individual. This characteristic is predictable and behaves as a recessive genetic when crossed with the brassy birds.

An interesting analogy to the STA WHITE characteristic occurred in the paint industry during the 1950’s.Try as they might, they couldn’t prevent the decolourisation caused by mildew in a relatively short time after application. This problem was especially troublesome in industrial areas. Chemists were called in to decide why the mildew attacked the paint surface so readily. They isolated the problem. The white pigment used in the paint had a lead base. This was combining with the relatively high levels of sulphur found in the air in industrial areas and formed mildew. The solution: replace the lead based white paint with titanium based pigment. With no lead now present in the paint, the sulphur alone was unable to cause surface mildew.

By the same reasoning the brassiness cannot occur in our white birds if we breed out this subdued red gene. This had been accomplished in nearly all strains of white Wyandottes and Leghorns. Some strains of white Cornish exhibit the STA WHITE characteristic and it sometime occurs spontaneously in other breeds.

Knowing this, what can the breeder do to eliminate brassiness in his stock?

Ken Herring, a well known Florida breeder of White Cornish in standards and bantams reports that he began developing his STA-WHITE strain in 1966. he used birds that displayed the least amount of brassiness and through careful selection, they evolved into fine specimens that were genetically free of brassiness by 1974. He currently maintains two strains of Cornish in which STA-WHITE is a fixed family trait. The results of Ken’s work over a period of several years further validate his conviction that STA-WHITE is heritable, and recessive in character.
Since Mendel’s Laws apply here, the ideal approach would be to produce a good male that exhibits STA-WHITE. Breed him to your best hens – even if they are brassy. All offspring will show brassy factor but when the best pullets are bread back to the father, statistically half their offspring will be STA-WHITE. Selected individuals from this cross can be used to produce your own line of STA-WHITE birds.

The STA-WHITE female is crossed with your best male, regardless of how brassy he is fine. Again, all offspring will be brassy. Select the best male from this group and breed him back to his mother. Statistically, half of the offspring will be STA-WHITE. Since only one female is involved the hatch will be only small. You can produce a few more STA-WHITES if cross a brother and sister from the offspring of the first generation. This cross will give 3 brassy to 1 STA-WHITE. Again, selected individuals from these crosses can be used to establish your line.

In both cases, your own strain of birds should remain virtually free from brassiness. This is true for two reasons. First, only a single outside bird has been introduced and second, a rigid careful selection of first and second generation birds would minimize the introduction of outside or undesirable influences.

Discuss / comment on this article in the poultry forum by clicking here