The oldest roo we ate was just about a year old. We roasted him in the oven with a cup of chicken broth in the pan (turkey dinner-style) at 325. He came out pretty good. Same as you, free ranged with organic feed available. I thought the five or six-month old rooster we cooked that way was a mite better, but my husband disagrees. It was quite flavorful.
That being said, I like a chicken with flavor, and haven't had many store chickens over the years because DH was a vegetarian for the first couple decades of our life together. So maybe someone who has gotten used to store chicken wouldn't like the taste of home-raised chicken as much?