That's basically what I'm asking. Whenever I see truly feral chickens that have existed in relative isolation for decades or centuries, they're always very small and lightning fast bantams
Will a large bird be able to replicate this success?
I suppose this is also asking, is the survival in your Large Survival Gamefowl for you or the chicken? I think small birds will always have the edge in true wilderness, but if it's about your survival and feeding your family then large gamefowl are far superior
I consider turkeys, peafowl, and many lessor known wild galliformes of similar size as being wild chickens of other varieties. Anything they can do, chickens can theoretically do, and those other galliformes survive well in larger sizes than red junglefowl or domestic bantams.
Larger chickens have a tendency to only survive feral on predator free-islands, while bantams and junglefowl are favored in typical forest situations. I believe this is because on the current chicken genetic continuum, the larger a chicken is, the more likely it is to have underdeveloped wings. It isn’t that large galliformes cannot fly, as wild turkey, peafowl, and others are good flyers. Its just so that currently there aren’t large chickens that have the same wing proportions as other large galliformes, nor are their flightless chickens that reach the same weights and swiftness as ratites so as to outclass many small predators directly on the ground.
I have found that in Florida, small bantams are subject to predation by smaller accipiters that normal sized chickens are immune to. My little Cracker hens are very susceptible to sharp shinned hawks. Sharp shinned hawks are adapted to catching song birds and no bantam will out class a song bird in swiftness of wing.
My terrorfowl can fly well enough to roost in trees and can glide short distances, but they prefer to run a lot more than my bankivoid gamefowl do. My goal for them is to be superior homestead free-rangers. I do not intend for them to be deep woods chickens that live like wild turkeys. That may be subject to change as I cross in more oriental gamefowl of turkey-like build.
I intend the Cracker improvement project to be the woods chickens that live like junglefowl. I believe the best survivors of those will be the largest birds that fly well and frequently. Somewhere will be a proper intersection between size and flight ability that will be the best of both worlds.