They had just separated her from the flock when I spoke with them, so I'm not sure yet. I will get a report in the morning and hopefully have more info.
My parents are dealing with a chicken that seems to be ill, and I thought you might have some insight. She has been staying on the coop floor tucking her head under her wing. Dad moved her to the run hoping she would eat or drink. She drank some when they dipped her beak. She won't eat food or...
My parents built a coop loosely based on the free plans from Purina. It turned out so well that they kindly helped build one for me. I'm really proud of it. I will try to post pics of theirs soon as well.
I think the "don't bring them in" advice is more about the humans than the chickens. Around 3 weeks you'll notice a layer of dust. Around 5 weeks you'll notice SEVERAL layers of dust. Smell and keeping them healthy should be no problem with good management and enough room.
Have you had the lamp on for 24 hours and do you have the top of the brooder partially covered to maintain heat? This may not apply to your set up, but the cover makes a difference and I recommend it even if you bring them inside. (You have to keep check on how they react still, of course.)