OK, this may seem like an insanely fussy set of instructions, but basic chicken stock is basic chicken stock, so this is not an amazingly different recipe, just a list of equipment and procedures that will allow you to make a gallon or so with minimal hassles. So the fussy instructions are the whole point.
Before you start, you need:
An instant-read thermometer A big bag of ice A deep sink or something that will serve the purpose (a big heavy plastic tub, etc.)
3 to 4 pounds of your favorite chicken bits (backs, necks, etc.).
One medium sized onion, cut in half pole to pole, root trimmed off but not peeled.
2 or 3 carrots, washed and sliced, but peeled only if they're dirty or you go "ick" at the thought of un-peeled. Or heck, save a few more minutes and just measure out an equivalent amount of "baby carrots." Either way, make sure they taste good and aren't bitter.
A gallon of water.
One decent enough pot big enough to hold all the ingredients plus a gallon of water.
A cheesy, quick to heat pot that will hold the chicken bits plus just enough water to cover (a crappy non-stick pasta pan with a glass lid is ideal)
One biggish bowl big enough to hold the chicken bits.
A pair of decent metal tongs.
A by-God stock skimmer -- get a Rosle at Surly Table and quit whining, your great grandkid will be using it.
And off you go. We're going to blanch these puppies (or necks and backs) first, a method I picked up from an Asian stock recipe and like because it eliminates most of the skimming by causing the crud to foam to the top immediately.
So, into the cheesy pot go the necks and backs with barely enough water to cover, boil covered as fast as possible. It will foam like hell when it boils, so be ready (a glass top is nice because you can watch it easily but still heat it rapidly).
Meanwhile, if you want, you can be cleverly heating up your good water in your good pot to save some time. Just bring it up to a simmer or near.
When it boils and foams up good (should look like dirty styrofoam on top), take off heat, and use your tongs (and the skimmer if need be) to remove all the chicken bits to your biggish bowl.
Sploosh, all the cruddy foam and water goes down the drain. You're done with that pot except for washing it up.
Just as a note, the foaming bit should take only a minute or two -- you don't want to boil the chicken into tastelessness.
Drag your bowl and the chicken bits over to the sink and rinse the bits off one by one under cold water. I scrub them slightly with my hands. This gets more of the crud off. And yes, if you want to get really fussy about it, you should have another clean bowl ready to put each one in after it's rinsed.
OK, into your good pot (with tongs unless you like being splashed with hot water) go the chicken bits, the carrots, and the halved onion.
Bring to simmer, and now we're into the usual bit. Simmer very gently uncovered for about 3 hours skimming as needed with the stock skimmer. It's ok to top up the liquid a bit if you want to make sure you end up with a gallon.
When you're satisfied, fill sink with water and ice. Use tongs and skimmer to remove as many of the bits, carrots, and onions as possible to your trusty biggish bowl (you're done with them, so you don't want to waste ice cooling them down).
Plunk your pot into the ice water, stirring occasionally, and measuring with your instant read thermometer until it gets down to a reasonable temperature (I try for about 60F).
Then take a the stuff out of the sink and use a ladle or whatever to transfer it to your overnight containers, pouring the stuff through a fine-mesh strainer.
Cool overnight in the fridge (if you're really paranoid, you can leave it uncovered in the freezer for a bit to cool it even further -- but don't forget about it).
The next day, skim the fat off the top, decant into your freezer storage containers -- again through the fine mesh strainer what the heck, label and freeze.
The great thing about this method is that there are no insane crisis points -- no lifting a 50-pound pot, no trying to fit 20 containers of stock in the fridge, no pots so tall they can hardly fit under your stove hood. The work is very spread out, everything always has a place to go, and none of the timing is critical. Because of this, you can easily do it (and I have) while cooking other stuff, and you don't dread doing it and keep putting it off until you run out of stock.