American gamefowl can handle extremes at both ends of the spectrum probably better than any other breeds. The oriental games can take the hot end very well. There is undoubtedly oriental game in the turken's genetic history. They expanded the bald patches common in oriental games, but with all of the mixing with standard barnyard variety chickens, they put really fluffy feathers on all of the parts that still have feathers. This is in contrast to the very thin layer of brittle feathers we see in the oriental gamefowl.
The Ga Noi Don is from Vietnam. It is really hot and humid there. When used for their historical purposes, they are expected to undergo extreme physical exertion for a long duration at around 100 degrees and near 100% humidity. To give an idea of the duration, the physical exertion was often in periods of a half hour with a ten minute rest break, and the number of cycles it might take to determine who was the best at exerting himself might not fit into a single 24 hour period. So selection toward heat tolerance was a given.
This has gone on for thousands of years, and at one point there was a prince exiled to a tiny Island near Africa, probably had some Ga Noi with him, and they probably gave rise to the Madagascar game and later the naked necks. So if you are giving thought to crossing extremely heat tolerant Vietnamese gamefowl to better egg producers to get a heat hardy egg layer, give up now, the work has already been done, and we have the turken. Now a little outcrossing to put the brittle feathers back on the turken would be an interesting project. Turkens that were less fluffy would be even better in heat, but the ones we have now do fairly good in heat in most places, yet can survive winter without special housing needs in most places. I had to breed feathers onto my Ga Noi to get them to survive a Virginia winter.