No free range does not mean Organic. I do not certify my chickens, so I do not know the specific rules for Organic eggs.
However one large problem I foresee with organic free range birds is you cannot control the insects. It is the same problem faced by beekeepers. Bees have a range of three miles, so unless you havea giant swath of organic land there is no such thing as organic honey.
I do not know the range of each insect but I imagine most have a large enough range to make organic free range impossible. I have a fully organic farm, so for my own use I am confident in my own eggs and chicken meat that freerange is not a issue for me. That said I do have commercial farmers as neighbors.
I feed my birds (in the winter) left over grains, organ meat, and they always have a non GMO feed available. I buy the feed from the guy we buy our organic seed from, i think it is the gleanings. He sells it for $18 a bag.
free range chickens-- do you still need to provide them feed ? or they will get enough food just from foraging already ?
I do not feed mine much, I have a feeder in the coop, however I do not have to add feed more than once a month during summer time. Winter it is every couple days.
The insect pop is just now getting great enough to sustain my birds, as soon as grasshopper season comes I will barely need to feed them at all. But then they begin needing more and more feed.