Organic does not automatically lead to flavor. If the organic chicken are raised in similar living conditions as non-organic factory-farmed chicken and the differences are mostly in the organic feed and antibiotics, the meat is going to taste similar.
True range birds that has the opportunities to eat bugs (e.g. pastured. or the example you cited) taste better. And they lead a more active life that minimizes the use of antibiotics anyway.
For a long time I ate a type of range chicken (Jidori) sold by a Japanese supermarket. Not organic, but the flavor compares favorably with top pastured organic chickens that are priced much higher. Unfortunately I moved away from the market.
