A series of crosses was made involving lightly-, and heavily-, and non-feather-shanked chickens in an attempt to clear up the confusion in the literature concerning the inheritance of feathered shanks in chickens. The Langshan and Brahma breeds were both shown to possess the same single shank-feathering locus, but because of their differences in phenotype and penetrance in the genetic crosses it was suggested that they possessed different alleles at this locus. This locus was designated as Pti-1, with Pti-1L being the Langshan allele and Pti-1B the Brahma allele. The Brahma allele was shown to be dominant over the Langshan allele. Both the Sultan and Cochin breeds were shown to possess two shank-feathering loci, and the data suggested that one of the loci in the Sultan contained the Pti-1L allele. It is hypothesized that the comparable allele in the Cochin breed was Pti-1B. It is proposed that the second locus in both of these breeds is similar, and the symbol Pti-2 is suggested.

Eight-week-old broilers of the three genotypes, normally feathered (na+/na+), heterozygous naked neck (Na/na+), and homozygous naked neck (Na/Na), were compared for growth performance and body composition characteristics at two environmental temperatures, 21 C in the cool room and 38 C in the hot room. Birds maintained in the cool room attained significantly greater live, New York dressed, and eviscerated weights than did birds maintained in the hot room, while consuming 93% more feed and achieving 84% greater weight gain. However, there were no significant differences in feed conversion ratios. Percent yield was 3% greater for birds in the hot room. In the cool room, na+/na+ birds were heavier than Na/Na birds for body weight measurements while in the hot room the reverse was true. In both temperatures the na+/na+ and Na/na+ birds were similar. For New York dressed percent yield, the Na/Na and Na/na+ were similar and had greater yield than na+/na+ birds in the cool room. The same trend held for birds in the hot room but to a much less degree. Eviscerated yield showed no genotype X temperature interactions. Body composition data indicated that Na/Na birds contained more moisture, similar protein, less lipid (particularly in cool room), and more ash (particularly in hot room) than the na+/na+ birds. Overall, in the hot environment, the Na/Na birds achieved significantly greater body weights than na+/na+ birds while containing less lipid but more moisture and ash.

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Two experiments were conducted in which featherless broilers (scaleless, sc/sc) were compared with feathered broilers for growth and body composition characteristics at environmental temperatures of 22, 34, and 38 C. The sc gene reduces growth and efficiency at 22 C but at 38 C the sc/sc broilers gain more, eat more, and are more efficient than feathered broilers. They achieve greater live, New York dressed, and eviscerated weights and consistently have greater eviscerated yields. The sc/sc broilers have more protein and mineral content and less fat than the feathered broilers.