Huh, I’ve never seen a 3 lb chicken for sale. I see 4-5 pound birds sold as “friers” and giant “oven stuffers”. I have seen smaller birds show up cooked on a restaurant plate, so i know they are sometimes slaughtered younger. But they aren’t raw available in my market.
You should be able to get away with a 3.5-4 pounder. I’m pretty sure I’ve used birds that big with the method, though I had to go for a few (5-10?) minutes longer. The Thomas Keller method does tend to put up some smoke, so I do put a water pan below to catch the drippings so they don’t burn. I know he says or the article says that it has to be absolutely dry, but I have not found the water pan adversely effects the results. It’s still crispy.
Well, it’s probably because people eat chicken as individual pieces, not in entire halves, so it makes sense to cook the individual pieces and serve them as such. Otherwise, you’re going to have to cut it up into pieces AFTER it is cooked, anyway, so it makes sense to cut it up when it is cool and dry and not hot and running juices all over the place.
I just checked today, and not store brand, but Perdue, and their regular chickens (their label says “Fresh Chicken Pollo Fresco” on it with no reference to fryer/broiler and the store sticker says “Perdue Whole Chicken USDA Grade A”) were 2.16 - 3.29 lbs. Most were around 2.7 lbs, from what I noticed. I bought the biggest one (3.29 lbs). There were bigger ones available in the 4-4.5 lb range, unbranded, but those were the sizes available here at my store in Chicago.
I like to cook roast chicken many different ways. Two nice ones are:
First way is in a cast iron pot. Heat some oil and butter and brown each side for a few minutes each. Add veggies if desired. Then bake in a preheated 250-300 degF oven until cooked, 45-120+ minutes depending on size. Remove chicken and let it sit ten minutes. Add wine and chicken broth to pan juices and boil until reduced to a gravy. Correct seasoning and add cornstarch if desired.
Second way is to slice potatoes thin, cover in Parmesan cheese and a grill. Bribe chicken if desired. Spatchcock chicken and make slits in skin. Rub butter and herbs in and roast chicken so fat drips onto cheesy potatoes.
What do you recommend? A bribe of about 15-18%? Bump up to 20% for an exceptional chicken?
I think I meant to type brine, and probably actually did type that before the helpful self-edit, but chickens can sometimes be bribed with an explanation about crossing the road or a bottle of wine.
IIRC there was an America’s Test Kitchen video where they spatchcocked a turkey but here was the real trick. They put the stuffing under the spatchcocked turkey so the drippings from the turkey got absorbed by the stuffing. I want to say they got the idea from Julia Child but not 100% on that.
EDIT to add: I think I found it but they put it behind a paywall:
Safeway out here sells them, but they’re pre-packaged with orange and herbs and who knows what else. I’ll stick to buying whole chickens and doing it myself. Takes longer to heat the oven. 
I have always seen spatchcock chicken used in the context of brick chicken. Basically put the chicken in a cast iron skillet, and then put a heavy weight ( some bricks wrapped in aluminum foil ) on top , then over direct heat for a bit then into the grill or oven on indirect heat. It’s supposed to give a crispy skin and moist chicken. Never tried it , but I feel an entry coming up un the "what’s for dinner " thread.
Here’s an Alton Brown one:
Chicken: Reloaded Recipe | Alton Brown | Cooking Channel (cookingchanneltv.com)
I saw one the next day after reading the post. It was an upper end market. What I noticed is it took up more shelf space than other ways of displaying chicken, and also it looked darn easy to do with a bird at home as part of the cooking prep. I would WAG that is your answer, it’s for those who shop at higher end markets who don’t mind paying more to avoid a minimal amount of prep (or lack the knowledge, bravery to do so). At this market it is also hard to find a rack of ribs, but easy to find a rack of ribs cut into nicely spaced ribs.
It really is. Anyone with a decent pair of kitchen shears and a chef’s knife can do it in a few minutes at home. Plenty of online guides to walk someone through it.
Yeah, having done it a grand total of once, it wasn’t hard. The only part that requires any finesse is removing the keelbone
Updating to say I’ve seen my first spatchcocked chicken in a store. And it was at my local Trader Joe’s.
I can only assume this thread has shifted the national paradigm.
Well, more important, did you buy it??
No, I had already bought a bunch of other groceries and I didn’t need a chicken sitting in my fridge.