When boning out whole processed grocery store chickens, the weight ratio of what you are left with (not counting giblets & neck if included) will be about 52% boneless meat, 20% skin and 28% bones.
So, for instance, to wind up with 12 lbs of bones you may need over 40 lbs of poultry.
Game birds may have different ratios, but not dramatically so. You may just have to keep track – and if you have too little for the size batch you want, you can always supplement with chicken.
Whether wild or store-bought, save the skins| Roasted then crumbled into the stockpot they add tremendous flavor. And for commercial chickens or turkeys, it lets you harvest much of the fat. Of course with wild birds that means you need to do a thorough plucking job… which can be a big hassle.
Normally the limiting factor for the number of “Servings” you are looking for is either the weight of bones you have available, or the capacity of your stock pot.
So fiddle with the pot size below until you come up with a number that is both a) not bigger than your biggest pot and b) not more bones than you expect to use. All of the other ingredients will fall into line.
Some of the boned meat will be called for in the stock recipe. It will be mostly leg meat, wings and if necessary some of the boneless thighs or breasts – depending what you prefer to keep for other purposes.
If starting with whole birds you’re likely to have a lot of boneless meat left over – plan in advance for how you want to use it. When done processing the birds, I salt the extra meat (dry-brining … google it), then vacuum seal in meal-size packages and freeze. It will partially dry-brine as it freezes, then the process completes when thawed for cooking. It’s super convenient – and dry-brined poultry is outstanding (adjust any salt in your recipes to allow for the salt you’ve already put in the meat). It’s more chicken than I normally need to have handy, so I share it with friends, neighbors or relatives.
Some stock recipes (including mine here) call for adding chicken feet for body. I always do that, but you can get a similar result with unflavored gelatin (google is your friend). If you don’t plan to save the wings (you monster!) they add some gelatin/body to your stock. Of course dry-brining and freezing the wings leaves a nice treat within easy reach.
If money is no object, try to get free-range or “pastured” birds. They get much more exercise, which builds up more cartilage and bone structure – which leads to better broth. But they are generally much MUCH more expensive than factory-farmed chickens. Making a big batch can be quite costly.