I got to say yes a bow would be much more quiet than a suppressor and subsonic ammo. However I don't thing It wound be the best way to go. what if there are lots of them in a group and you can't pull out the arrow or the arrows break due to the hard skull or the weight of the body if it falls the wrong way? plus Rapid fire is impossible and making decent arrows that would fly straight and also making the stone arrow needed to penetrate a skull would take forever. I guess you could find the right wood and harden it with fire but you would have to be close to penerate the skull and get the brain. love how quiet it would be but not so good when it comes to close range effectiveness and the time to make the arrows,wings, and you have to look around for long straight sticks, it would be totally different from the walking dead where an hour later you have 30 perfectly make combat ready arrows
also I saw your site, nice to know I'm not the only one who thinks it takes a wolf to stop a wolf. If SHTF it won't change human nature people need to understand there will be good and evil, and the bad people will prey on the good people. I've always been a problem solver and would deal with people who become a problem