Yes, it's happened again: One our little Nankin bantam hens came out of the bushes yesterday with 3 chicks, which had clearly hatched quite recently. We were just getting into the car to run into town to do some errands when I thought I heard baby bird-like peeping nearby. It only took a minute to find the mama and babies; then David discovered the nest, which still had unhatched eggs in it! One of the eggs was pipped (the chick had broken a hole in it) and although the egg was a bit cool, we could see the chick was moving.
Fortunately I had just cleaned out one of the broody coops, and it had fresh straw in it. I went inside to get a feeder and drinker, while David started gathering up chicks and eggs. In just a few minutes, mama, babies and eggs were happily settled in a nest out of the rain and away from potential predators.
Chickens incubate their eggs for 21 days, so this hen had been outside in the bushes, with very little shelter from the weather, for 3 weeks. Normally hens will get up off the nest once a day; they prefer to poop away from the eggs, and also they like to get something to eat and drink every so often, and maybe take a quick dust bath. These little Nankins go broody quite frequently, and are very attentive and protective moms. They also seem to prefer to nest away from the coops, and they free-range all day, so it's not all that uncommon for one of them to show up with a brood of chicks.
We decided to just leave them be for a day or so, then we will check to see how many additonal chicks have hatched. As we recently sold some of our Nankins to the Oregon Zoo in Portland, we were thinking about hatching some more anyway. And as usual, the Nankins are a step ahead of us!