I normally harvest heritage Cockerels around 16 weeks. I have done some at 6 months.
How do you age and cook the 16 week ones? Any different than the six month ones?
I try to harvest my dual purpose cockerels between 16 and 23 weeks of age. I'd like to wait until 23 weeks for all of them but I spread them out so I only butcher a few at a time and I sometimes need to manage freezer space. The way I cook them all is to cut them into parts and rinse them off. Then I coat them in herbs and put them in a baking pot that seals well. I bake them in the oven at 250 degrees Fahrenheit for about 2-1/2 to 3 hours. That is not a typo, 250. You need a tight fitting lid so it doesn't cook dry and burn.
When you take it out of the pot carefully use a slotted spoon. You should have maybe a half cup of liquid that is a great chicken broth. If you are not careful the meat might fall off the bone. I freeze mine the day I butcher them but put them in the fridge Sunday for cooking on Thursday so they can thaw and age.
I also freeze the rest of the carcass, back and neck, along with the gizzard and heart. I also keep the feet, scalding them and removing the claws and spurs, and skin the feet. That gets the feet clean enough for me but some people may not want to use them. I save the bones from when I cooked the parts and use all of this to make chicken broth.
I put all these parts into a crock pot, add a bay leaf, a dozen peppercorns, a carrot, celery, onion, garlic, and some herbs, top it off with water, and cook that overnight on low. Eight hours will work but I usually go closer to 18 to 20 hours. I strain the liquid out and de-fat it. That usually yields around six pints of the best chicken broth you will ever taste.
There are a lot of different ways to cook a bird that age and have then come out delicious. You don't have to make broth, it can be time consuming and there are a lot of different ways to do that, but I'd consider it a waste if I didn't. Their age is what gives the texture and extra flavor much more than them walking around. Their hormones kicking in has a lot to do with that extra texture and flavor. You do have to cook them differently than the chicken you buy at the store that is butchered at 6 to 8 weeks before those hormones kick in. But it does not have to be tough.
Good luck.
