Linky:
www.albc-usa.org/documents/cookingwheritagechicken.pdf
I love eating old chickens!
The main thing to cook an old boy is LOW heat.
Think about how tough cuts of meat are best cooked, like slow BBQed ribs or brisket. You don't want to get over 200 degrees for heat. Now of course, the USDA and FDA will have a fit about saying that, but then, they regulate meat that's been processed assembly line and not at home with care.
This also includes cooking a roo in water - water boils at 212 - over 200 degrees. You need a nice slow simmer to make him tender and fall off the bone - like a crock pot on low (not high - high usually gets a low boil going).
I have dry roasted a 1yr+ old roo, and he turned out great - same deal, stuck him in the oven at a very low temp, and let him cook the day away until the inside temp was 165. He was delish!
Also make sure to rest him well. I like to rest my older birds for about 3-4 days in the fridge to really get all the rigor out and let nature take it's course to start softening the tissue.
You can click on My BYC page under my avatar for a page about eating dual purpose and older birds