So, I was convinced that both of our 22 week old barred rocks were laying eggs, but we've been keeping a close eye on the birds and it appears we were wrong. One bird -- Mathilda -- is doing all the heavy lifting.
Mohawk makes all the same noises, but we're fairly certain that she's not laying. We scoured the yard and their run and the coop: she's not hiding them.
Our current (admittedly lazy) plan is to just sit back and wait it out. I don't know what else we could do. Mohawk is not a rooster. She looks nearly identical to Mathilda and at 22 weeks, she doesn't have any rooster-ish characteristics.
They're eating laying feed and we have some oyster shell out for them to grab if they so choose.
My only real concern is that Mohawk will start laying while we're on vacation, in which case we won't be there to deal with any emergencies. That's ok, though, because our neighbors are chicken owners themselves, so ours will be in good hands.