Thanks Yashar for posting the photos of the two Green Mountain breeds. To be clear, there are two separate breeds depicted. The top two photos are of the Green Mountain Copper Scotch. The Green Mountain Black Jack is a totally different breed. It's been bred to produce a heavier carcass and darker eggs than the Copper Scotch.
There is no Polish blood in any of the Green Mountain breeds. As I outlined earlier, the Copper Scotch have been select bred from high altitude breeds from Ecuador; Switzerland and Tibet. The Polish is actually an Indonesian breed imported recently to Europe where it is was select bred for ornamental qualities.
The Green Mountain breeds are specifically designed for life in exceedingly cold regions and very high altitudes.
I must be a stickler here because it is too often the case that hobbyists underestimate the significance of selective breeding and cultural/geographical origination of different breeds.
This is significant to our conversation here because it relates directly to selecting appropriate breeds for regional environments versus taking inappropriate breeds and attempting to adapt enclosures around the breed. Serious farmers will take note that replacing hens every few years via hatcheries is not a sustainable or particularly ethical practice. Small farms around the country and the world are moving away from big commercial utility breeds. This is because they generally tend to be relatively short-lived and inefficient energy converters, which lack the capacity to self-perpetuate. Its more economically feasible and sustainable for many farmers to maintain small flocks of New Heritage or Cultural Heritage breeds, The New Heritage breeds like the Iowa Blue or Green Mountain Copper Scotch; or Old Cultural Heritage breeds like the Egyptian Fayoumi or Levantine Lakenvelder for example.
Here are some scientific references and an abstract involving the value of selective refinement of domestic strains using rare cultural heritage blood stock as it relates to extreme cold and altitude factors.
Frontiers of Agriculture in China
Volume 2, Number 2, 237-241, DOI: 10.1007/s11703-008-0030-6
Research Article
Influences of altitude on growth curves in Tibetan chicken and its hybrid
Hao Zhang, Changxin Wu, Yangzom Chamba, Yao Ling and Suling Ji
Journal Article
Effect of mating combination and environmental factors on hatchability of chicken eggs in Tibet
Delin Mo, Kui Li, Yangzong Qiangba, Xiaohui Tang and Mengjin Zhu, et al.
Frontiers of Agriculture in China, 2007, Volume 1, Number 2, Pages 214-219
Journal Article
Study on Tibetan Chicken embryonic adaptability to chronic hypoxia by revealing differential gene expression in heart tissue
Mei Li and ChunJiang Zhao
Science in China Series C: Life Sciences, 2009, Volume 52, Number 3, Pages 284-295
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Journal Article
Ten polymorphic microsatellite loci in Tibetan chicken, Gallus gallus domesticus
Kong Yang, Xia Luo, Yong Wang, Ying Yu and Zhihua Chen
Conservation Genetics, 2010, Volume 11, Number 3, Pages 671-673
Journal Article
Genetic Variation of the Peroxisome Proliferator-Activated Receptor α Gene (PPARA) in Chickens Bred for Different Purposes
J. Q. Zhang, H. Chen, Z. J. Sun, X. L. Liu and Y. Z. Qiang-Ba, et al.
Biochemical Genetics, 2010, Volume 48, Numbers 5-6, Pages 465-471
Journal Article
Differential gene expression of phosphoglyceric kinase (PGK) and hypoxic adaptation in chicken
CunFang Wang, CunZhong Yuan, Lao Zhang, ChangXin Wu and Ning Li
Science in China Series C: Life Sciences, 2007, Volume 50, Number 3, Pages 335-342
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Journal Article
Eight trinucleotide microsatellite DNA markers from Tibetan chicken, Gallus gallus domesticus
Kong Yang, Xia Luo, Yong Wang, Ying Yu and Zhihua Chen
Conservation Genetics Resources, 2009, Volume 1, Number 1, Pages 225-227
Journal Article
Sequencing and alignment of mitochondrial genomes of Tibetan chicken and two lowland chicken breeds
HaiGang Bao, ChunJiang Zhao, JunYing Li and ChangXin Wu
Science in China Series C: Life Sciences, 2008, Volume 51, Number 1, Pages 47-51
Journal Article
Analysis of genetic structure and relationship among nine indigenous Chinese chicken populations by the Structure program
H. F. Li, W. Han, Y. F. Zhu, J. T. Shu and X. Y. Zhang, et al.
Journal of Genetics, 2009, Volume 88, Number 2, Pages 197-203
Journal Article
Analysis of genetic diversity and phylogenetic relationships among red jungle fowls and Chinese domestic fowls
WenBin Bao, GuoHong Chen, BiChun Li, XinSheng Wu and JingTing Shu, et al.
Science in China Series C: Life Sciences, 2008, Volume 51, Number 6, Pages 560-568
Journal Article
Analysis of genetic diversity and phylogenetic relationships among red jungle fowls and Chinese domestic fowls
WenBin Bao
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Abstract
Tibetan chicken is a precious resource in Qinghai-Tibet Plateau, China. In order to study its growth rhythm and heterosis of its hybrid, three groups comprising Tibetan chicken (T), Dwarf Recessive White (D) and Tibetan × Dwarf Recessive White (TD) were reared under the same management conditions at low and high altitudes. Body weight and shank length were measured, and growth curves were fitted using Richards model. The results showed that the model fitted well with the chickens growth courses in weight and shank with R 2 at more than 0.99. The high-altitude might retard the growth of chickens, with decreases in inflection point values, final values and maximal growth rates, and prolongation of inflection point time. The final weight, inflection point weight, and maximal growth rates of Tibetan chicken were 1008.3 g, 477.9 g and 11.69 g respectively at lowaltitude, and 525.3 g, 229.5 g, and 5.12 g at high-altitude. This showed a decline of 47.9%, 52.0%, and 56.8% at the high-altitude; the degree of influence of altitude was less than that of Dwarf Recessive White. The TD had high heterosis in weight gain, and at high-altitude the heterosis of final weight, inflection point weight, and maximal growth rates were 59.5%, 56.8% and 52.3% respectively. Therefore, the Tibetan × Dwarf Recessive White cross was good for improving the Tibetan chicken.
Keywords Tibetan chicken - growthcurve - altitude - Richards model - heterosis
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Translated from Journal of China Agricultural University, 2007, 12(2): 4044 [译自: 中!!! PLEASE REPORT THIS IMMEDIATELY !!!农!!! PLEASE REPORT THIS IMMEDIATELY !!!大!!! PLEASE REPORT THIS IMMEDIATELY !!!!!! PLEASE REPORT THIS IMMEDIATELY !!!报]