1/4 chicken per person is a generous serving. So, my suggesting is to cook 10-12 and save the rest for a whole nother casserole entree- it would be plenty for another meal. I included a chicken and rice recipe at the end.

A roaster oven can be used in many different ways, from roasting (the obvious one!), to slow-cooking, to steaming, and poaching. The key is to not overcook the meat or allow it to fry in its own fat.

So how about doing pieces:

cooking by temperature rather than time is essential

Remove the cooking well. Preheat the covered roaster for 20 minutes to 425-450 degrees F.

Rinse the birds or pieces under a running tap of cool water.

Place chicken, olive oil, and any seasoning in Ziploc bag and seal. Shake to coat chicken with ingredients. Per whole chicken or 4 quarters, a nice spicy amount is:
2 teaspoons salt
1 teaspoon paprika
3/4 teaspoon cayenne pepper
1/2 teaspoon onion powder
1/2 teaspoon thyme
1/4 teaspoon white pepper
1/4 teaspoon garlic powder
1/4 teaspoon black pepper
1 large onion -- quartered

Lightly spray inside of the cooking well with cooking spray. Remove chicken pieces from Ziploc bags and arrange them in the cooking well of the preheated roaster. Stuff the onions in the chickens or scatter the quartered onions among the pieces, especially if you plan to do soup from the bones.

Place the cooking well in the preheated roaster. Reduce temperature to 375 degrees F. Roast 25 to 45 minutes, approximately 20 minutes per pound, this works for the weight of pieces or the weight of whole chickens. When the cooking time is up, check to see that the bird is done by inserting an instant-read thermometer into the meatiest part of the thigh. The internal temperature should be 165 degrees F. If it’s not done, bake it for an additional 20 minutes.

The carcasses can make a rich broth.
Put the carcass right back into the cookwell, without washing it first (lets those tasty brown bits get into the soup.) Add the roasted onions, any bones, skins, bits. For each whole chicken carcass or 4 quarters, a tablespoon or or two of cider vinegar, a few stalks of celery,a clove or two of garlic, a teaspoon of dried ginger, and enough water to cover by about 3 inches. Let it slow slow cook overnight at 250. Let the broth cool, remove the solids and strain and chill.
The fat rises to the top and can be removed.

I put the roaster pan right on the rack, fill it in the oven, cover tightly. When done, instead of lifting the hot heavy pan, slide the rack part way out and use tongs to transfer meat to your cutting board.

Day of, make your sauce in 3 roasters, put 1/3 the meat in each one, heat it up in the hot sauce.

Anna, you can't chill this chicken fast enough to keep safe once cooked unless you have a freezer or two, or 4-5 empty refrigerators.

You need to cool fast in ice baths 30 minutes or less to in shallow baggies or pans, then transfer no more than about 30 pounds to any refrigerator, in 8-10 pound max amounts. Poultry products, including ground poultry, should always be cooked to at least 165 °F internal temperature as measured with a food thermometer; storage temp refrigerated 40 degrees within two hours after cooking.

DO NOT stack the baggies, or they won't stay cold enough, must be 40 or bacteria can grow.

If you are planning to keep cold in ice chests, layer single layers of bagged chicken with equally thick layers of bagged ice. and replenish the ice if/as it melts.

Reheat thoroughly and quickly, to at least 75°C/165°F. You have only 2 hours from removing from chill through to 160 degrees/ serving. Once reheated it cannot safely be frozen and reheated again.

Insulate when traveling. If you’re taking a dish to a party or to work, be sure to keep it hot (over 160) or cold (under 40) until the moment you leave and then ensure that it stays that way by carrying it in an insulated carrier.