thai chickens keep the spurs but cut the combs ;philipines use knives, maybe he was used as a baiter for fighing?: (like the poor dogs that are used to train fighting pitbulls)?
anyhow, most fighting chickens respond as if fighting when approached from the front, chest level or over the head. when we want to pick up our birds, we put our open hands really under their bellies and talk to them, then we can pick them up and pet them or clean them... ours are 6months old but even as chicks they already go for moving hand in front of their line of vision (as if it were an other chicken facing them off).
when being trained, handlers use their hands as if they were a chicken with a beak, so a flat hand facing up is not perceived as much of a threat... thats what i know of the thais and their chickens, so u can maybe try to aproach him that way...
will be hard to retrain since a fighting chicken is dna wired to respond, its not jsut training but the personality built in and the dna has been augmented by training and practice....
btw, they are intelligent birds and can be taught vocal cues for coming to you , and for moving away from u, if u have the time and patience, but dont expect him to be docile or a pet (definately not if u have a young child that is small. these chickens can jump quite high. and thier peck draws blood (if u havent found that out yet).
btw, he will start with any other chicken if u release him in the neighborhood and he will kill other chickens: they do a kung fu kick to the chest that can kill a young foolish challenger that isnt from his own 'group'. ours square off all the time, and we stop them before it can become a fight.
i tend to agree, soup might be best (actually chopped up stir fry for this bred, its game meat, not white chicken meat). (also, if he was worth something, he wouldnt be wondering around the nighborhood but still someone's prize pet, so possibly he is at the end of his career, or lost too often, or whatever).
whatever u do, dont feed him from your hands, feed him from a dish. will prevent injuries to your arms.