Well,
From my experience I'll say I'm not real keen on tough old roosters! We butchered one of our two roosters a couple weekends ago. He was a bit over a year old, 100% free range. He had gotten really mean (kept going after my 4 year old daughter) so that was the end of him!
I let him 'rest' in the fridge for a full 24-hours. Then I boiled the stuffin' out of that bird! A regular store bought broiler would have been nothing but mush in the bottom of the pot!
His breast meat (what there was of it, he was a RIR and a lean one at that from chasing hens and kids all day) was good enough to eat straight off the bones, but his thighs and legs were so tough I gave up on them. I couldn't even get the meat off the bones without a serious tug-of-war. Decided I didn't want to even try to eat that! Threw them out to the cats and chickens (yea, that's a fitting end... the hens finally got to tear into him for a change!).
If the chickens have been kept caged they might be more tender. You could tell looking at my guy that he'd lived a good, free life. Even the 'white' breast meat was dark! Exercise = dark meat = tough meat with time! I'm sure there are recipes to deal with the effects of time, but I'm not privy to them.
Liz