Sounds just like my hen. My 4-year-old BR has been like this for weeks now and still not sure what's wrong. I took a fecal sample to my vet that came back negative for parasites. She's eating and drinking though not as much as usual, walks slowly, tail down, poops fine, some weight loss, lots of...
We built a 42" fence around two sides of the garden and coop/run a month or so ago. The chickens are happy to stay in the fenced area so far. Two of our three chickens have flown to the top of the fence, but they haven't gone to the other side (yet). We have a 6-foot block wall that surrounds...
They like to lay in the dark so I wouldn't put a window in the nest area. A door to the nesting box is a great idea, whatever makes it easier for you to collect eggs.
Are you feeding the chicks mealworms? If so, they need grit in order to digest them. The best thing is probably to just give them the starter feed for now.