Oh fun suspense! What kind are you getting?
Bee would you get a feed with 15% protein or 22%? My flock ranges from 19 weeks up to a year with 2 roosters. I just didn't want to have to feed different kinds for chicks vs layers. I have oyster shell out on the side and no real problems with thin shells. I am hoping for broody hens this year too and I know that chicks need more protein. What are your suggestions?
I'd go with the 15%...it's going to be cheaper and it will be more than adequate for all ages and sexes. I'm not a fan of upping proteins as I've never really seen much difference between the two in regards to flock health and production levels, so why pay for the difference?
This reminds me ... I need to write to the heritage breed conservancy group and ask them why their website recommends feeding heritage breed chickens 28% protein feeds even as adults,

When I was shopping for feed of that high protein percentage (for poults) in our area it wasn't much fun, and I don't want to have to go through that again if there isn't any scientific reason to justify it.
Since I saw that advice I've been doing tons of research into protein percentages and poultry performance and health and the best I can come up with is that the 15%-17% feeds are the most efficient for mature layers except during molt, but that also birds can do better with more protein, but specifically do better with some animal proteins in the mix.
Then there are always vague warnings about too much protein potentially causing health problems, but reports vary greatly on what "too much" is.

It only occurred to me the other day I should just write to the group and ask them directly.

I have both chickens and ducks, and usually have birds or multiple ages & both genders, and therefore we feed an all-purpose poultry feed that starts at 19%, and then dilute it with grains, oyster shell on the side. We prefer this base food & the complementary scratch mix for lots of reasons, one of which is we can get it at a local feed mill instead of the farm store where the help in the feed department isn't terribly helpful.
There is a handy little calculator over at the Metzer Farms website that will tell you how much of two different feeds to mix together to get to your target protein percentage ... http://www.metzerfarms.com/FeedConversion.cfm
People with excellent forage don't have to sweat it as much because the birds will self-regulate the macronutrient balance in their diet ...
And of course they say fermenting the feed makes it more nutritious ...
This is one of those things that can become overcomplicated pretty quickly, so I've been working on streamlining the feeding process from start to finish. And improving the foraging options for the birds.