We've been eating our homegrown rooster culls and the occasional hen for 3 years now and enjoy them immensely. I find it very satisfying to be self sustainable in this way.
The first year was U of A RIR culls. These were on the scrawny side as any hatchery "dual purpose" stock would be (I don't think that any hatchery stock is really dual purpose) but were delicious and tender with proper crockpot cooking. Second year with my own culls from good heritage RIR and White Chantecler breeding stock, were a vast, vast improvement over year one stock (like night and day really), no scrawny birds here and depending on age, were delicious roasted or crockpot. Year three from my selection process is showing great results for meat qualities both good size and rate of growth.
Two of my 4 1/2 month old Chantecler cockerels graced our Christmas table this year and were served with pride to our guests. (I'm not yet raising my own turkeys and this year I just could not bring myself to buy the commercial product). They were roasted whole and were tasty, tender, and delicious. Without exaggeration, our guests were delighted at how tender and delicious my homegrown roosters were and that made me very happy
. Feed 10 people with leftovers for 5 more servings followed by soup for another 6 servings.
This is how we process our roosters/hens:
We take our culls calmly to slaughter. I've think this is an important first step. We don't let them see or hear others getting done and get stressed about it. I handle my roosters a lot so they are hugged and calmed before I pass them over to my husband to do the final deed. My husband is very good at doing the deed quickly and effectively and we contain the flapping about to prevent bruising and additional toughening of the meat.
I hand pluck as we only butcher our culls as we want to eat them (no room in the freezer). If we decided to butcher our culls en masse, I would probably invest in a plucker or send them to a processor because the arthritis in my fingers would make it very difficult to handle more than 3 at a time. I have read that auto plucking can make the meat tougher; I can't attest to how true that is or to what degree they are toughened if not hand plucked, it's just what I do.
I let them rest in the fridge. This is easy when you only do 1 to 3 birds at a time. Once they are cleaned they are popped into an extra large zip lock bag and rest in the fridge for a minimum of 2 days before they are cooked or frozen. I rest older birds (around 1 yr old or older) for 3 days.
Initially I only brined the older roasters but now I do the young roasters as well. It takes about 2 minutes to prepare the brine, then pour it into the zip lock bag and pop the chicken back into the fridge for a few hours (depending on the size). When you're ready to plop them in the roaster, give it a good rinse and you're done. It does not make the meat salty (unless you don't rinse of course). The brining helps keep the meat moist and the meat is so tasty!!
Roast your chicken upside down. This is a trick I learned a long time ago, long before we dined on our home grown heritage chickens. When you roast upside down, all the juices from roasting go down to the parts you want to eat instead of draining down into the back area. Okay the skin on the breasts is not browned but who cares, the chicken is carved before it hits the table anyways.
For older birds at one year or older, you can get fantastic results using a crock pot.