Move slowly , talk quitely , Set out treat from them in a certian spot far enough from you for them to feel safe then you can move it closer to you every week . If you have the time and money you might try and open coop with treats left inside. IF they are truley wild chickens chances are you wont ever get to close to them. But if you leave lots of nice places to lay eggs you can just collect the eggs every day and store them for 7-10 till you have enough then hatch them in an incubator. They like crickets , meal worms , scratch , might try some spent grains from a brewery , or fermented feed, as well as tamatoes and some greens. If they are wild think of them more like feral cats. Long term you can get there trust to come close to feed but thats about it they most likely will never be handleable. I would just suggest getting them as friendly as you can but just gather eggs and hatch your own.