The Madagascar study is based on DNA mapping. Hereunder some results regarding studies about the origin of African chicken. I copied some original parts out of these studies with source reference.....
Mitochondrial DNA Origin of Indigenous Malagasy Chicken (2008) by
Hanta Razafindraibe & others.
(study text)......We report the mitochondrial DNA (mtDNA) characterization of 77 indigenous chickens (fighting and meat birds) from Madagascar....The most common haplogroup was present in 65 individuals of the two types; it is likely of Indonesian origin. The second haplogroup was observed in 12 fighting birds and meat chickens; it could be of African continental origin and/or the result of recent introgression with commercial lines......(end)
Remark: Orlando, this is a joint venture study with the University of Antananarivo (Madagascar), International Livestock Research Institute Nairobi (Kenya) and Chinese Academy of Agricultural Sciences (China)
Lack of phylogeographic structure of Nigerian chicken revealed by mitochondrial DNA D-loop sequence analysis (2005) by A. O. Adebambo & others.
(study text)......Reference sequences representing the major chicken mtDNA lineages from Asia indicate the Indian sub-continent to be the main source of Nigeria local chickens....(end)
Mitochondrial DNA D-loop sequences suggest a Southeast Asian and Indian origin of Zimbabwean village chickens (2008) by F. C. Muchadey & others.
(study text)......Results indicated the existence of two distinct maternal lineages evenly distributed among the five Zimbabwean chicken ecotypes. For one of these lineages, chickens from Zimbabwe and Malawi shared major haplotypes with chicken populations that have a Southeast Asian background. The second maternal lineage, probably from the Indian subcontinent, was common to the five Zimbabwean chicken ecotypes, Sudanese and Northwest European chickens as well as purebred broiler and layer chicken lines....(end)
Diversity and origin of South African chickens (2011) by B. J. Mtileni & others
(study text).....Four South African conserved chicken populations (n = 89), namely, Venda (VD_C), Ovambo, Naked Neck, and Potchefstroom Koekoek from the Animal Production Institute of the Agricultural Research Council, and 2 field populations, the Venda and Ovambo....All 6 South African chickens were equally represented in the major clade, E, which is presumed to be of Indian subcontinent maternal origin and may have its roots in Southeast Asia. The results showed multiple maternal lineages of South
African chickens. Conservation flocks and field chicken populations shared the major haplotypes A, D and E, which were presumed to be of Chinese, Southeast Asian, and Indian subcontinental origin....(end).
Orlando, I think that the final conclusion regarding the origin of African chicken is not Africa but the Indian subcontinent and Southeast Asia. Regarding the Madagascar nakedneck fowl and their Indonesian origin, in Bali and maybe also on other Indonesian islands you find nakedneck (with smooth skin) gamefowl !
Source publication Aneka Ayam Hias (1991) by Frans Sudiro